Sandbox WWC11: Difference between revisions
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'''Introduction''' | '''Introduction''' | ||
Myeloperoxidase (MPO) is a protein found in nertrophil, the most common white blood cell. This enzyme generates hypochlorous acid (HOCl) from hydrogen peroxide in addition to other hypohalous acids depending on what is available in the cell. The HOCl is then used, in combination with other molecules, in an oxidative burst that kills bacteria and other potentially harmful invaders one taken up by the cell. This protein falls into a group of heme peroxidase enzymes. The role of these enzymes is to oxidize molecules using the heme<ref name="Hampton">PMID:9787133</ref>. | Myeloperoxidase (MPO) is a protein found in nertrophil, the most common white blood cell. This enzyme generates hypochlorous acid (HOCl) from hydrogen peroxide in addition to other hypohalous acids depending on what is available in the cell. The HOCl is then used, in combination with other molecules, in an oxidative burst that kills bacteria and other potentially harmful invaders one taken up by the cell. This protein falls into a group of heme peroxidase enzymes. The role of these enzymes is to oxidize molecules using the heme<ref name="Hampton">PMID:9787133</ref>. | ||
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'''Structure''' | '''Structure''' | ||
Myeloperoxidase is synthesized in bone marrow along with most other white blood cell components. The myloperoxidase enzyme is composed of two identical subunits. After translation of these subunits, they are cleaved into two parts: the heavy chain and the light chain. The heavy chain is a glycosylated domain that weighs approximately 58.5kDa. This portion of the enzyme has the deep pocket where the heme is inserted into by chaperones(calreticulin and calnexin). <ref name="Neutrophil">PMID:26904693</ref> The amino acid make up of heme pocket can be seen in Figure 1. The pink in this picture is the light chain, the blue is the heavy chain. The light chain (about 13.5kDa) is attached to the heavy chain through disufide bonds. There have been discoveries of slight variation in the primary sequence of myeloperoxidase. However, for the most part these slight variations do not affect the enzymatic activity. Currently three isoforms have been isolated. <ref name="Enzymatic Activity">PMID:120019</ref> | Myeloperoxidase is synthesized in bone marrow along with most other white blood cell components. The myloperoxidase enzyme is composed of two identical subunits. After translation of these subunits, they are cleaved into two parts: the heavy chain and the light chain. The heavy chain is a glycosylated domain that weighs approximately 58.5kDa. This portion of the enzyme has the deep pocket where the heme is inserted into by chaperones(calreticulin and calnexin). <ref name="Neutrophil">PMID:26904693</ref> The amino acid make up of heme pocket can be seen in Figure 1. The pink in this picture is the light chain, the blue is the heavy chain. The light chain (about 13.5kDa) is attached to the heavy chain through disufide bonds. There have been discoveries of slight variation in the primary sequence of myeloperoxidase. However, for the most part these slight variations do not affect the enzymatic activity. Currently three isoforms have been isolated. <ref name="Enzymatic Activity">PMID:120019</ref> | ||
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'''Function''' | '''Function''' | ||
Image | Image | ||
Figure 2. The Enzymatic Activity of Myeloperoxidase. | Figure 2. The Enzymatic Activity of Myeloperoxidase. <ref name="Myeloperoxidase">PMID:21297906</ref> | ||
As stated before, the role of the myeloperoxidase in the immune response is to generate oxidative molecules that are used to damage invaders. Seen above in Figure 1 is a concise and basic diagram of the process. Compounds I, II and III are the different oxidation states of the iron in the heme molecule. One of the processes facilitated by myeloperoxidase is to oxidize hydrogen peroxide (H2O2) and cause the iron to change oxidation states. In this state, the iron is then able to catalyze the production of the hypohalous acids. These molecules are able to reek havoc on lipids, proteins and DNA. <ref name="Neutrophil">PMID:26904693</ref> These modifications are achieve by the oxidation (usually the addition of the halogen) of the unlucky recipient. The heme iron can also be oxidized by radicals to form compounds II and III. The functions of these are less well known, but the productions of these radicals is also helpful in the antibacterial response.<ref name="Myeloperoxidase">PMID:26884610</ref> | As stated before, the role of the myeloperoxidase in the immune response is to generate oxidative molecules that are used to damage invaders. Seen above in Figure 1 is a concise and basic diagram of the process. Compounds I, II and III are the different oxidation states of the iron in the heme molecule. One of the processes facilitated by myeloperoxidase is to oxidize hydrogen peroxide (H2O2) and cause the iron to change oxidation states. In this state, the iron is then able to catalyze the production of the hypohalous acids. These molecules are able to reek havoc on lipids, proteins and DNA. <ref name="Neutrophil">PMID:26904693</ref> These modifications are achieve by the oxidation (usually the addition of the halogen) of the unlucky recipient. The heme iron can also be oxidized by radicals to form compounds II and III. The functions of these are less well known, but the productions of these radicals is also helpful in the antibacterial response.<ref name="Myeloperoxidase">PMID:26884610</ref> | ||
