Proteopedia - User contributions [en]

Copper, Zinc Superoxide Dismutase

2010-04-01T03:02:48Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1">RCSB Protein Data Bank.(2007). http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from cellular molecules essential for proper cell function, causing dysfunction and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Devlin, Thomas M. (2006). Textbook of Biochemistry with Clinical Correlations 6th Ed. Wiley-Liss, Hoboken NJ. p.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray, R., Bender, D., Botham, K. Kennelly, P. Rodwell, V. Weil, P. (2006). Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. p.484-485</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg, J. Tymoczko, J. Stryer, L. (2007). Biochemistry 6th Ed. W.H. Freeman and Company, NY. p.518-519</ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref>Seeley, R.R, Stephens, T.D, Tate, P. (2008). Anatomy & Physiology (8th ed.). New York, NY: McGraw Hill</ref>

Current studies are showing one of the long-term benefits of exercise may be by increasing the amount of superoxide SOD in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes with a protective net effect, because the increase in SOD more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-04-01T02:41:49Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1">RCSB Protein Data Bank.(2007). http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from cellular molecules essential for proper cell function, causing dysfunction and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Devlin, Thomas M. (2006). Textbook of Biochemistry with Clinical Correlations 6th Ed. Wiley-Liss, Hoboken NJ. p.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray, R., Bender, D., Botham, K. Kennelly, P. Rodwell, V. Weil, P. (2006). Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. p.484-485</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg, J. Tymoczko, J. Stryer, L. (2007). Biochemistry 6th Ed. W.H. Freeman and Company, NY. p.518-519</ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref>Seeley, R.R, Stephens, T.D, Tate, P. (2008). Anatomy & Physiology (8th ed.). New York, NY: McGraw Hill</ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-04-01T01:23:51Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1">RCSB Protein Data Bank.(2007). http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Devlin, Thomas M. (2006). Textbook of Biochemistry with Clinical Correlations 6th Ed. Wiley-Liss, Hoboken NJ. p.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray, R., Bender, D., Botham, K. Kennelly, P. Rodwell, V. Weil, P. (2006). Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. p.484-485</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg, J. Tymoczko, J. Stryer, L. (2007). Biochemistry 6th Ed. W.H. Freeman and Company, NY. p.518-519</ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref>Seeley, R.R, Stephens, T.D, Tate, P. (2008). Anatomy & Physiology (8th ed.). New York, NY: McGraw Hill</ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-04-01T01:09:54Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Devlin, Thomas M. (2006). Textbook of Biochemistry with Clinical Correlations 6th Ed. Wiley-Liss, Hoboken NJ. p.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray, R., Bender, D., Botham, K. Kennelly, P. Rodwell, V. Weil, P. (2006). Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. p.484-485</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg, J. Tymoczko, J. Stryer, L. (2007). Biochemistry 6th Ed. W.H. Freeman and Company, NY. p.518-519</ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref>Seeley, R.R, Stephens, T.D, Tate, P. (2008). Anatomy & Physiology (8th ed.). New York, NY: McGraw Hill</ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-04-01T01:02:32Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Devlin, Thomas M. Textbook of Biochemistry with Clinical Correlations 6th Ed. Wiley-Liss, Hoboken NJ. 2006. p.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray R., Bender D., Botham, K. Kennelly, P. Rodwell, V. Weil, P. Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. 2006. p.484-485</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg J., Tymoczko J., Stryer L., Biochemistry 6th Ed. W.H. Freeman and Company, NY. 2007. p.518-519 </ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-04-01T00:58:59Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Metabolic Pathways and their Control pg.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Murray R., Bender D., Botham K., Kennelly P., Rodwell V., Weil P., Harper's Illustrated Biohemistry. 28th Ed. McGraw Hill. 2006.</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Berg J., Tymoczko J., Stryer L., Biochemistry 6th Ed. W.H. Freeman and Company, NY. 2007. </ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T22:01:55Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu, Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Metabolic Pathways and their Control pg.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu, Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu, Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T21:57:16Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu, Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu, Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu, Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Metabolic Pathways and their Control pg.574</ref>.

=====General Structure=====
Cu, Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu, Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu, Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human Cu, Zn SOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T18:18:39Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu/Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu/Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. The cytosolic and extracellular enzymes,both containing Cu/Zn as their active sites and the mitochondrial enzyme contains Mn at its active site<ref name="placeholder4">Metabolic Pathways and their Control pg.574</ref>.

=====General Structure=====
Cu/Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu/Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu/Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen<ref name="placeholder3"> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref name="placeholder4"/>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref name="placeholder3"/>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T18:02:08Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu/Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu/Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isozyme isozymes] of SOD. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Cu/Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu/Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu/Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T17:43:55Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Cu/Zn superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Cu/Zn superoxide dimustase belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] SOD. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Cu/Zn SOD is a metalloprotein with a structural weight of 62913.70, containing both copper and zinc ions in each subunit, each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-ligand region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix and the smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane. The protein was solved from X-Ray difraction with 2.0Å<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Cu/Zn SOD catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes, together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu/Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T02:20:26Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
Copper, zinc superoxide belongs to the family of [http://en.wikipedia.org/wiki/Oxidoreductase oxidoreductases]known as [http://en.wikipedia.org/wiki/Superoxide_dismutase Superoxide Dismutase (SOD)]. In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] SOD. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Cu/Zn SOD is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8. Symmetrically related β bulge pairs fold the two large loops back against the external surface of the β barrel to surround the active channel. The active site Cu(II) and Zn(II) lie 6.3 Å apart at the bottom of this long channel; the Zn is buried, while the Cu is solvent-accessible. The side-chain of His61 forms a bridge between the Cu and Zn and is coplanar with them within the current accuracy of the data. The Cu ligands ND1 of His44 and NE2 of His46, −61 and −118 show an uneven tetrahedral distortion from a square plane.<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Cu/Zn SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T01:53:46Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase(SOD)]. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
*[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]
*[http://www.ncbi.nlm.nih.gov/pubmed/17888947 Structural characterization of zinc-deficient human superoxide dismutase and implications for ALS]
==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T01:42:54Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase(SOD)]. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8<ref>PMID:7175933</ref>.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Oxidative Capabilities and Importance of Vitamins==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>. If
SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>. Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis familial amyotrophic lateral sclerosis (ALS)] patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T01:27:50Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; it serves as the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death. Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase(SOD)]. Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8<ref>PMID:7175933</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>.

Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>

Over 130 mutations to copper, zinc superoxide dismutase (SOD) are implicated in the selective death of motor neurons found in 25% of familial amyotrophic lateral sclerosis (ALS) patients. ALS is an adult onset disease involving the progressive death of lower motor neurons in the spinal cord and upper motor neurons in the brain stem and cortex<ref>PMID:17888947</ref>

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T01:07:23Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death.

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8<ref>PMID:7175933</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>.

Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens, Tate </ref>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-30T00:57:46Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accepts electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their function and possibly resulting in cell death.

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by detoxifying the superoxide radical via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known [http://en.wikipedia.org/wiki/Isomer isomers] of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc ions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

Each enzyme subunit is composed primarily of eight antiparallel β strands that form a flattened cylinder, plus three external loops. The largest loop includes both a disulfide region and a Zn-liganding region, each of which resembles one of the other two loops in overall structure. The second largest loop includes a short section of α helix. The smallest loop forms a Greek key connection across one end of the β barrel. The single disulfide bond, which forms a left-handed spiral, covalently joins the largest loop to the beginning of β strand 8<ref>PMID:7175933</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are highly reactive molecules with an unpaiared electron in an outer orbital, which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital<ref>Metabolic Pathways and their Control pg.574</ref>.

Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref name="placeholder"/>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-29T16:45:06Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.

== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="placeholder">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by catalyzing the dismutation of the superoxide radical to hydrogen peroxide and water via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase is a metalloprotein, containing both copper and zinc anions in each subunit, where copper acts as the active site. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper, zinc superoxide dismutase catalyzes the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. Copper, zinc superoxide dismutase takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also dangerous and needs to be detoxified. The cells use the enzyme [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen.

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with aging. Antioxidants, such as beta carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref name="placeholder"/>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-29T04:58:12Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="placeholder">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by catalyzing the dismutation of the superoxide radical to hydrogen peroxide and water via a special reaction known as dismutation <ref name="placeholder2">PMID:12906825</ref>. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

It is a metalloprotein.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack. Mutations in human CuZnSOD are associated with the development of familial amyotrophic lateral sclerosis (motor neuron disease)<ref name="placeholder2"/>

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

However, hydrogen peroxide is also a dangerous compound and needs to be converted to water and molecular oxygen. The cells use the enzyme catalase to detoxify it. [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with age.Antioxidants, such as beat carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref name="placeholder"/>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-28T18:50:15Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final electron acceptor in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce a large amount of energy from our food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="placeholder">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. It forms a crucial component of the cellular response to oxidative stress by catalyzing the dismutation of the superoxide radical to hydrogen peroxide and water via a special reaction known as dismutation <ref>PMID:12906825</ref>. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Copper, zinc superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

It is a metalloprotein.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.
Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with age.Antioxidants, such as beat carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref name="placeholder"/>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-28T18:42:06Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref name="placeholder1"> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="placeholder">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref name="placeholder1"/>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.
Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with age.Antioxidants, such as beat carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref name="placeholder"/>

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-26T23:24:45Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.
Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Free radicals are molecules that can react and alter the structure of molecules that control the normal cell function of the cell. According to the free radical theory, this damage can accumulate with age, leading to the normals symptoms seen with age.Antioxidants, such as beat carotene, vitamin C, and vitamin E, can donate electrons to free radicals, without themselves becoming harmful. Thus, antioxidants may prevent the damage caused by free radicals and may ward off age-related disorders, ranging from wrinkles to cancer. Experiments designed to test this hypothesis, however, have not consistently produced positive results<ref> Seeley, Stephens & Tate. pg1113</ref>.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-26T22:54:36Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical, a molecule that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. They are molecules with a highly reactive unpaiared electron in an outer orbital,which can initiate chain reactions by removal of an electron from another molecule to complete its own orbital <ref>Metabolic Pathways and their Control pg.574</ref>. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==The Reaction of Dismutase==
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.
Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.
Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>

Copper, Zinc Superoxide Dismutase

2010-03-26T21:35:38Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis], [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Copper, zinc superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Copper, zinc superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.
<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide.
[[Image:Fig2.gif]]

Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.
Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>
Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T21:22:16Z

Jordan Schibli:

'''Copper, zinc superoxide dismutase''' is an oxidoreductase enzyme responsible for the very rapid two-step dismutation of the toxic superoxide radical to molecular oxygen and hydrogen peroxide through alternate reduction and oxidation of the active-site copper<ref>PMID:6316150</ref>.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor<refname="two">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide. Most enzymes that produce and require superoxide are in the peroxisomes,together together with superoxide dismutase, catalase and peroxidases<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest <ref> Oxidative Phosphorylation Ch.18, pg. 518 </ref>.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>
Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T18:53:43Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor<refname="two">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

<ref>PMID:6316150</ref>

==References==
<references/>
Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T01:53:51Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing]<ref name="one">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref> .

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor<refname="two">Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref>http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide<ref>Free Radicals and Antioxidant Nutrients ch.6 pg.484</ref>.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>
Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T01:32:28Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2).

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor<ref>Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion <ref name="rasmol">http://www.rcsb.org/pdb/explore/explore.do?structureId=2SOD</ref>.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>
Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T01:22:40Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound.<ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>. Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2).

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor<ref>Seeley, Stephens, Tate., Anatomy & Physiology, 8th edition, McGraw Hill, 2008</ref>.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
<references/>
Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T00:46:48Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2).

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen (4).

2H2O2 → 2H2O + O2

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

Copper, Zinc Superoxide Dismutase

2010-03-26T00:26:29Z

Jordan Schibli:

'''Cu/Zn Superoxide dismutase''' is an oxidoreductase enzyme responsible for the detoxification of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce much more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2).

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen. This enzyme detoxifies superoxide via a special reaction known as dismutation. Cu/Zn Superoxide dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-26T00:11:48Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====

Cu/Zn Superoxide dismutase`s protein structure was solved by X-Ray Difraction at 2.00 Å resolution. It is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70 with the ligand identifier of C2 H4 O. Cu/Zn Superoxide dismutase contains six disulfide bonds with each subunits active site containing a copper and zinc ion.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-26T00:02:30Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

=====Superoxide Dismutase Family=====
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

=====General Structure=====
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules <ref> http://www.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb94_1.html</ref>.

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-25T23:17:26Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Oxidative Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-25T21:48:21Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation Dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-25T21:37:00Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation Dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|left|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
texttext<ref>PMID:#(specific#)</ref> (1)

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-25T21:35:28Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation Dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

[[Image:SOD1.png|thumb|Cu/Zn Superoxide dismutase polypeptide chain coloured by B-factors]]

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
texttext<ref>PMID:#(specific#)</ref> (1)

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

File:SOD1.png

2010-03-25T21:32:05Z

Jordan Schibli: Cu-Zn Superoxide dismutase chain

Cu-Zn Superoxide dismutase chain

Copper, Zinc Superoxide Dismutase

2010-03-25T21:10:16Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

Superoxide is produced both accidentally and also as a reactive oxygen species required for a number of enzyme-catalyzed reactions. Copper-Zinc superoxide dismutase catalyze the reaction between superoxide and water to yield oxygen and hydrogen peroxide.

[[Image:Fig2.gif]]

Hydrogen peroxide is then scavenged by [http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the [http://en.wikipedia.org/wiki/Dismutation Dismutation]of hydrogen peroxide into water and molecular oxygen (4).

<math>2H_2 O_2 → 〖2H〗_2 O + O_2 </math>

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death (2). Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==See Also==
[http://en.wikipedia.org/wiki/Free-Radical_Theory Free-Radical Theory of Aging (FRTA)]

==References==
texttext<ref>PMID:#(specific#)</ref> (1)

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed. (2)

RCSB

Free Radicals and Antioxidant Nutrients ch. 6 pg. 484

[http://en.wikipedia.org/wiki/Cancer Cancer]

Copper, Zinc Superoxide Dismutase

2010-03-25T20:39:56Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration at the
[http://en.wikipedia.org/wiki/Electron_transport_chain electron transport chain], allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in [http://en.wikipedia.org/wiki/Amyotrophic_lateral_sclerosis Amyotrophic lateral sclerosis] (ALS), [http://en.wikipedia.org/wiki/Arteriosclerosis Arteriosclerosis], [http://en.wikipedia.org/wiki/Arthritis Arthritis], [http://en.wikipedia.org/wiki/Cancer Cancer], and [http://en.wikipedia.org/wiki/Ageing#Theories Ageing](2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of [http://en.wikipedia.org/wiki/Superoxide_dismutase superoxide dismutase] (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==
[[Image:Fig2.gif]]

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by
[http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase is a [http://en.wikipedia.org/wiki/Homotetrameric homotetramer], containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==References==
texttext<ref>PMID:#(specific#)</ref>

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed.

RCSB

[http://en.wikipedia.org/wiki/Cancer Cancer]

[http://en.wikipedia.org/wiki/Ageing#Theories Ageing]

Copper, Zinc Superoxide Dismutase

2010-03-25T20:14:04Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration, allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in Amyotrophic lateral sclerosis (ALS), arteriosclerosis, arthritis, cancer, and aging (2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of superoxide dismutase (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==
[[Image:Fig2.gif]]

[http://en.wikipedia.org/wiki/Dismutation Dismutation] is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by
[http://en.wikipedia.org/wiki/Catalase catalase], a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase is a heterotetramer, containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide are a type of [http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species] that can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==References==
texttext<ref>PMID:#(specific#)</ref>

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed.

RCSB

[http://en.wikipedia.org/wiki/Reactive_oxygen_species reactive oxygen species]

[http://en.wikipedia.org/wiki/Dismutation dismutation]

[http://en.wikipedia.org/wiki/Catalase catalase]

Copper, Zinc Superoxide Dismutase

2010-03-25T19:22:28Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Oxygen is vital to sustain life; our cells cannot live without it. Oxygen is the final acceptor of electrons in respiration, allowing us to produce more energy from food. But oxygen is also a dangerous compound (1). Reactive forms of oxygen, such as superoxide, leak from the respiratory chain and wreak havoc on the cell. Superoxide is a free radical; radicals are molecules that readily accept electrons, which make them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in Amyotrophic lateral sclerosis (ALS), arteriosclerosis, arthritis, cancer, and aging (2). Superoxide dismutase is an enzyme that detoxifies superoxide via a special reaction known as dismutation.

Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

==Superoxide Dismutase Family==
In mammals there are three known isomers of superoxide dismutase (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism.

==The Reaction of Dismutase==
[[Image:Fig2.gif]]

Dismutation is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules (1).

The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase is a heterotetramer, containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Free radicals such as superoxide can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==References==
texttext<ref>PMID:#(specific#)</ref>

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed.

RCSB

Copper, Zinc Superoxide Dismutase

2010-03-24T01:12:32Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
[[Image:Superoxide_dismutase.png|thumb|Cu/Zn Superoxide Dismutase]]
Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

Dismutation is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide. Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.

==The Reaction of Dismutase==
[[Image:Fig2.gif]]

In mammals there are three known isomers of superoxide dismutase (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism. The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase is a heterotetramer, containing four polypeptide chains (B,O,G,Y), 152 residues in length. Each chain contains one alpha-helix and 12-14 beta-sheets. It has a structural weight of 62913.70. It has a ligand identifier of C2 H4 O

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Antioxidant Capabilities==
Superoxide dismutase is involved in eliminating a free radical, known as superoxide, from the body. Free radicals are molecules that readily accept electrons, which makes them highly reactive. They can strip electrons from proteins, lipids, or nucleic acids, thereby destroying their functions and resulting in cell dysfunction or death. Free-radical damage has been implicated in Amyotrophic lateral sclerosis (ALS), arteriosclerosis, arthritis, cancer, and aging. Superoxide is one of the most important free radicals. Although oxygen is critical for aerobic metabolism, it is also dangerous to tissues. SOD catalyzes the conversion of superoxide to hydrogen peroxide, which is then converted by catalase to oxygen and water. Apparently, if SOD is defective, superoxide is not degraded and can destroy cells. Motor neurons appear to be particularly sensitive to superoxide attack.

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==References==
texttext<ref>PMID:#(specific#)</ref>

Seeley, Stephens, Tate. (2008). Anatomy & Physiology 8th Ed.

Copper, Zinc Superoxide Dismutase

2010-03-23T21:29:12Z

Jordan Schibli:

File:Fig2.gif

2010-03-23T21:26:14Z

Jordan Schibli: Superoxide dismutase reaction

Superoxide dismutase reaction

Copper, Zinc Superoxide Dismutase

2010-03-23T21:17:05Z

Jordan Schibli:

Copper, Zinc Superoxide Dismutase

2010-03-23T20:49:27Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

Dismutation is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide. Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.

==The Reaction of Dismutase==
In mammals there are three known isomers of superoxide dismutase (SOD). Copper and Zinc containing SOD1 is located in the cytoplasm. Manganese containing SOD2 is located in the mitochondria while a second Copper and Zinc containing SOD3 is located in the extracellular space. SOD3 and SOD2 are tetramers whereas SOD1 is a dimer. These enzymes perform the dismutation reaction by a similar mechanism. The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase contains four polypeptide chains (B,O,G,Y). Each chain contains one alpha-helix and 12-14 beta-sheets.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

[[Image:Superoxide_dismutase.png|alt text]]

==References==
texttext<ref>PMID:#(specific#)</ref>

File:Superoxide dismutase.png

2010-03-23T20:45:16Z

Jordan Schibli:

Copper, Zinc Superoxide Dismutase

2010-03-19T20:16:51Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

Dismutation is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide. Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.

==The Reaction of Dismutase==
Eukaryotes contain two forms of this enzyme, a manganese-containing version located in mitochondira and a copper- and zinc-dependent cytoplasmic form. These enzymes perform the dismutation reaction by a similar mechanism. The oxidized form of the enzyme is reduced by superoxide to form oxygen. The reduced form of the enzyme, formed in this reaction, then reacts with a second superoxide ion to form peroxide, which takes up two protons along the reaction path to yield hydrogen peroxide.

The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen.

==General Structure==
Cu/Zn Superoxide dismutase contains four polypeptide chains (B,O,G,Y). Each chain contains one alpha-helix and 12-14 beta-sheets.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==Importance of Vitamins==
Superoxide dismutase and catalase are remarkably efficiently, performing their reactions at or near the diffusion-limited rate. Glutathione peroxide also plays a role in scavenging H2O2. Other cellular defences against oxidative damage include the antioxidant vitamins, vitamins E and C. Because it is lipophilic, vitamin E is especially useful in protecting membranes from lipid peroxidation.

One of the long-term benefits of exercise may be to increase the amount of superoxide dismutase in the cell. The elevated aerobic metabolism during exercise causes more ROS to be generated. In response, the cell synthesizes more protective enzymes. The net effect is one of protection, because the increase in superoxide dismutase more effectively protects the cell during periods of rest.

==References==
texttext<ref>PMID:#(specific#)</ref>

Copper, Zinc Superoxide Dismutase

2010-03-19T20:12:03Z

Jordan Schibli:

'''Cu/Zn Superoxide Dismutase'''
Cu/Zn Superoxide (SODc) dismutase is an oxidoreductase enzyme, catalyzing the dismutation of superoxide into oxygen and hydrogen peroxide.
== Introduction ==
Cu/Zn Superoxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen.
Cu2+ Zn Superoxide Dismutase belongs to the superfamily of oxidoreductases, specifically those acting on superoxide as acceptor.

Dismutation is a term that refers to a special type of reaction, where two equal but opposite reactions occur on two separate molecules. SOD takes two molecules of superoxide, strips the extra electron off of one, and places it on the other. So, one ends up with an electron less, forming normal oxygen, and the other ends up with an extra electron. The one with the extra electron then rapidly picks up two hydrogen ions to form hydrogen peroxide. Of course, hydrogen peroxide is also a dangerous compound, so the cell must use the enzyme catalase to detoxify it.

==The Reaction of Dismutase==
2 O2 -. + 2H+ SOD> 02 + H2O2

==General Structure==
Cu/Zn Superoxide dismutase contains four polypeptide chains (B,O,G,Y). Each chain contains one alpha-helix and 12-14 beta-sheets.

<applet load='2SOD' size='300' frame='true' align='right' caption='Cu/Zn Superoxide Dismutase' />

==References==
texttext<ref>PMID:#(specific#)</ref>