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https://proteopedia.org/api.php?action=feedcontributions&feedformat=atom&user=Megan+M.+Roy Proteopedia - User contributions [en] 2026-10-02T20:29:14Z User contributions MediaWiki 1.43.8 https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588836 Human gastric lipase 2016-04-28T14:29:58Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />.<br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == External Links ==<br /> <br /> PDB - 1HLG: http://www.rcsb.org/pdb/explore.do?structureId=1HLG<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588835 Human gastric lipase 2016-04-28T14:29:07Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />.<br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == External Links ==<br /> <br /> Refer to PDB - 1HLG article for a comprehensive summary of structure and function: http://www.rcsb.org/pdb/explore.do?structureId=1HLG<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588834 Human gastric lipase 2016-04-28T14:27:53Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />.<br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == External Links ==<br /> <br /> Refer to PDB article on Human Gastric Lipase for further structural and functional information: http://www.rcsb.org/pdb/explore.do?structureId=1HLG<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588832 Human gastric lipase 2016-04-28T13:48:18Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />.<br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == External Links ==<br /> <br /> Wikipedia page on HGL: https://en.wikipedia.org/wiki/Gastric_lipase<br /> <br /> PDB page on HGL: http://www.rcsb.org/pdb/explore.do?structureId=1HLG<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588831 Human gastric lipase 2016-04-28T13:39:08Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />.<br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == External Links ==<br /> <br /> https://en.wikipedia.org/wiki/Gastric_lipase<br /> <br /> http://www.uniprot.org/uniprot/P07098<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588770 Human gastric lipase 2016-04-28T02:54:56Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL secretion <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588769 Human gastric lipase 2016-04-28T02:53:01Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural Highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) was therefore found to be altered in adolescents with gastritis; in support of this finding, it has been suggested in existing literature that GLP-1 and CCK inhibit HGL action <ref name="glp">PMID:9558037</ref><ref name="cck">PMID:10425652</ref>. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588622 Human gastric lipase 2016-04-27T17:40:06Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must depend heavily on HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily on HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588620 Human gastric lipase 2016-04-27T17:35:44Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase) must rely heavily upon HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588618 Human gastric lipase 2016-04-27T17:35:02Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase, which also catalyzes the hydrolysis of triglycerides) must rely heavily upon HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588617 Human gastric lipase 2016-04-27T17:33:31Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />. Furthermore, individuals with compromised pancreatic function (and therefore reduced levels of pancreatic lipase, which also catalyzes the hydrolysis of triglycerides) must rely quite heavily upon HGL in order to digest dietary fats <ref name="armand" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588616 Human gastric lipase 2016-04-27T17:23:51Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/4'>Lid</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588614 Human gastric lipase 2016-04-27T16:59:47Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728237/1hlg_lid_and_catalytic_arm/1'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588609 Human gastric lipase 2016-04-27T16:47:00Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis) <ref name="armand" />. These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely primarily upon HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588608 Human gastric lipase 2016-04-27T16:45:30Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis reaction of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of HGL is crucial in premature infants, who often exhibit poor pancreatic function <ref name="armand" />, as well as adults with pathologic pancreatic insufficiency (e.g., chronic pancreatitis). These individuals are unable to produce adequate amounts of pancreatic lipase and must therefore rely upon more heavily HGL for the digestion of dietary fats <ref name="armand" />. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588602 Human gastric lipase 2016-04-27T16:33:42Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> The hydrolytic action of HGL is somewhat ancillary in healthy adults, in whom HGL modulates 10-20% of dietary fat breakdown at most <ref name="armand" />. However, the presence of this enzyme is crucial in premature infants, as well as those who are otherwise unable to produce sufficient levels of pancreatic lipase due to pancreatic insufficiency. In these individuals, HGL is responsible for hydrolyzing 30-60% of dietary triglycerides <ref name="armand" />.<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588438 Human gastric lipase 2016-04-26T13:34:41Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Human_gastric_lipase&diff=2588437 Human gastric lipase 2016-04-26T13:34:21Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> *Human gastric lipase* (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587956 Sandbox 78 2016-04-20T18:52:40Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of HGL at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587955 Sandbox 78 2016-04-20T18:51:32Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis (the most common gastric condition, in which the stomach lining is inflamed) <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with ''Helicobacter pylori'' gastritis (''n'' = 10), another experimental group consisting of adolescents with a non-''H. pylori'' induced form of gastritis (''n'' = 10), and one control group of healthy adolescents (''n'' = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than ''H. pylori'' exhibited lower levels of HGL activity compared to both healthy adolescents (''p'' < .005) and those who were diagnosed with ''H. pylori'' gastritis (''p'' < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (''p'' < 0.005) than in those with non-''H. pylori'' gastritis (''p'' < .003) and those with ''H. pylori'' gastritis (''p'' < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587954 Sandbox 78 2016-04-20T18:46:08Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> that contains residues Ser-153, His-353, and Asp-324. This structure is essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis (the most common gastric condition, in which the stomach lining is inflamed). HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587953 Sandbox 78 2016-04-20T18:43:09Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric [[hydrolase]] enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis (the most common gastric condition, in which the stomach lining is inflamed). HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587952 Sandbox 78 2016-04-20T18:42:41Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| The hydrolysis of triacylglycerol that is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits a mechanism resembling the established serine esterase mechanism. The active site serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The tetrahedral species is stabilized by the oxyanion hole. However, as soon as the species disassembles into the covalently bonded acetate and lipase, the serine undergoes deacylation in which water acts as the nucleophile. This final step restores Ser-153 to its protonated state <ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of HGL secretion in children and adolescents with gastritis (the most common gastric condition, in which the stomach lining is inflamed). HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587949 Sandbox 78 2016-04-20T18:33:25Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/5'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587948 Sandbox 78 2016-04-20T18:32:04Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/4'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587947 Sandbox 78 2016-04-20T18:30:31Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/3'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587946 Sandbox 78 2016-04-20T18:26:21Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The <scene name='72/728060/1hlg_lid/2'>"Lid"</scene> of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2587943 Sandbox 78 2016-04-20T17:57:28Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is the [[lipase]] that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an <scene name='72/728060/Arm_and_hole/1'>Oxyanion Hole</scene> at Leu-67 and Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple). The "lid" of the lipase at residues 215-244 <ref name="dogs">PMID:20965171</ref> gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid. These areas are thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586586 Sandbox 78 2016-04-12T01:08:52Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple), where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine, located within the <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene>, is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586585 Sandbox 78 2016-04-12T00:57:37Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, <scene name='72/728060/Secondary_structure/1'>Secondary Structure</scene> (beta sheets shown in yellow, alpha helices shown in orange, coiled coils shown in green, and amino acid side chains shown as purple), where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL <ref>Adapted from [http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/enzymes/GetPage.pl?ec_number=3.1.1.3]; image generated using [https://www.emolecules.com]</ref>.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586300 Sandbox 78 2016-04-10T20:22:20Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a dimeric enzyme consisting of two 379 amino acid residue-long subunits, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated <scene name='72/728060/Secondary_structure/1'>Conformation</scene>, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968M</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586272 Sandbox 78 2016-04-10T19:55:38Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This acid-stable enzyme <ref name="gastritis">PMID:23899880</ref> is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis" />.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated <scene name='72/727839/Secondary_structure/1'>Conformation</scene>, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL.]]<br /> <br /> HGL functions at an optimal pH of approximately five, and primarily catalyzes the hydrolysis of short-chain triacylglycerols <ref name="kinetic assay">PMID:3743968M</ref>.<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586267 Sandbox 78 2016-04-10T19:44:51Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This pH-stable enzyme is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis">PMID:23899880</ref>.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated <scene name='72/727839/Secondary_structure/1'>Conformation</scene>, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|400px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL.]]<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586265 Sandbox 78 2016-04-10T19:43:37Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This pH-stable enzyme is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis">PMID:23899880</ref>.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a <scene name='72/728060/Catalytic_elbow/3'>Catalytic Arm</scene> consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated <scene name='72/727839/Secondary_structure/1'>Conformation</scene>, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the <scene name='72/728060/Hydrophobic_regions/1'>Hydrophobic Areas</scene> (hydrophobic regions noted in red) both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|300px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL.]]<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> Tomasik et al. (2013) <ref name="gastritis" /> investigated the hormonal regulation of human gastric lipase secretion in children and adolescents with gastritis -- the most common gastric condition, in which inflammation occurs in the lining of the stomach -- as there is little existing literature regarding this subject. HGL activity was compared across three groups: one experimental group consisting of adolescents diagnosed with Helicobacter pylori gastritis (n = 10), another experimental group consisting of adolescents with a non-H. pylori induced form of gastritis (n = 10), and one control group of healthy adolescents (n = 14). HGL activity, in addition to plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide, were observed through analysis of gastric juice samples that had been collected via endoscopic measurements from each patient.<br /> <br /> Patients whose superficial gastritis was induced by pathogens other than H. pylori exhibited lower levels of HGL activity compared to both healthy adolescents (p < .005) and those who were diagnosed with H. pylori gastritis (p < .005). Mean plasma concentrations of glucose-dependent insulinotropic peptide were lower in healthy patients (p < 0.005) than in those with non-H. pylori gastritis (p < .003) and those with H. pylori gastritis (p < 0.01). Regulation of HGL secretion by glucagon-like peptide-1 and cholecystokinin was therefore found to be altered in adolescents with gastritis. In addition, glucose-dependent insulinotropic peptide was found to be a powerful activator of human gastric lipase activity in all experimental and control groups <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586226 Sandbox 78 2016-04-10T19:11:13Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' scene='72/728060/Catalytic_elbow/1' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Hydrophobic and Hydrophilic Regions of Human Gastric Lipase' scene='72/727839/Hydrophobic_and_polar_regions/1' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Secondary Structure of Human Gastric Lipase' scene='72/727839/Secondary_structure/1' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This pH-stable enzyme is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis">PMID:23899880</ref>.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a catalytic arm consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated conformation, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the hydrophobic areas both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|300px|left|thumb| Hydrolysis of triacylglycerol. This reaction is catalyzed by HGL.]]<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> A study was completed to discover the understanding of hormonal regulation of gastric lipase secretion in children and adolescents, as this is still very limited. <br /> <br /> The activity of human gastric lipase was compared among two experimental groups and one control group. The control group included 14 healthy adolescents. The experimental groups were one group of 10 patients diagnosed with ''Helicobacter pylori'' gastritis, and another group of patients exposed to other pathogens besides ''Helicobacter pylori'' to cause gastritis. The activity of human gastric lipase was observed through endoscopic measurements within the collected gastric juice from each patient. The plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide were determined in all patients as well. <br /> <br /> This study suggested that the activity of human gastric lipase activity was changed in patients that were diagnosed with superficial gastritis induced by pathogens other than ''Helicobacter pylori''. The level of activity of human gastric lipase was significantly lower in patients with superficial gastritis than in patients that were healthy (p<0.005) and were diagnosed with ''Helicobacter pylori'' gastritis (p<0.005). The mean levels of glucose-dependent insulinotropic peptide plasma concentrations were lower for patients in the control group (p<0.005) than in non-''Helicobacter pylori'' gastritis and ''Helicobacter pylori'' gastritis patients (p<0.01). The regulation of human gastric lipase secretion by glucagon-like peptide-1 and cholecystokinin was found to be altered in those whom had gastritis. Glucose-dependent insulinotropic peptide in both healthy and gastritis-diagnosed patients was found to be a powerful controller of human gastric lipase activity <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2586225 Sandbox 78 2016-04-10T19:10:13Z

<p>Megan M. Roy: </p> <hr /> <div><Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' scene='72/728060/Catalytic_elbow/1' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Hydrophobic and Hydrophilic Regions of Human Gastric Lipase' scene='72/727839/Hydrophobic_and_polar_regions/1' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Secondary Structure of Human Gastric Lipase' scene='72/727839/Secondary_structure/1' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This pH-stable enzyme is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis">PMID:23899880</ref>.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a catalytic arm consisting of residues Ser-153, His-353, and Asp-324 essential to the breakdown of lipids, coordinated with an oxyanion hole Leu-67 Gln-154 <ref name="dogs">PMID:20965171</ref>, that serves to stabilize the transition state. Structurally, the human gastric lipase exhibits a complex, coordinated conformation, where the "lid", residues 215-244 <ref name="dogs">PMID:20965171</ref>, of the lipase gives way to the hydrophobic areas both surrounding the active site and interfacing the lid, thought to draw lipids and promote docking <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> [[Image:Hydrolysis triacylglycerol reaction.png|300px|left|thumb| Hydrolysis of triacylglycerol.]]<br /> <br /> As an esterase with a catalytically active serine, HGL exhibits an established serine esterase mechanism. The active serine is facilitated first by the neighboring formation of a salt bridge between Asp-136 and His-152, which induces the appropriation of a proton from Ser-153. The now highly nucleophilic Ser-153 will attack the carbonyl carbon of the acetate group in a triacylglycerol molecule. The now tetrahedral species, stabilized by the oxyanion hole; however, as soon as the species disassembles into the covalently bonded acetate and lipase, and the serine undergoes deacylation where water acts at the hydroxyl group. This final step restores Ser-153 to its protonated state<ref name="esterase">PMID:23209280</ref>. <br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> A study was completed to discover the understanding of hormonal regulation of gastric lipase secretion in children and adolescents, as this is still very limited. <br /> <br /> The activity of human gastric lipase was compared among two experimental groups and one control group. The control group included 14 healthy adolescents. The experimental groups were one group of 10 patients diagnosed with ''Helicobacter pylori'' gastritis, and another group of patients exposed to other pathogens besides ''Helicobacter pylori'' to cause gastritis. The activity of human gastric lipase was observed through endoscopic measurements within the collected gastric juice from each patient. The plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide were determined in all patients as well. <br /> <br /> This study suggested that the activity of human gastric lipase activity was changed in patients that were diagnosed with superficial gastritis induced by pathogens other than ''Helicobacter pylori''. The level of activity of human gastric lipase was significantly lower in patients with superficial gastritis than in patients that were healthy (p<0.005) and were diagnosed with ''Helicobacter pylori'' gastritis (p<0.005). The mean levels of glucose-dependent insulinotropic peptide plasma concentrations were lower for patients in the control group (p<0.005) than in non-''Helicobacter pylori'' gastritis and ''Helicobacter pylori'' gastritis patients (p<0.01). The regulation of human gastric lipase secretion by glucagon-like peptide-1 and cholecystokinin was found to be altered in those whom had gastritis. Glucose-dependent insulinotropic peptide in both healthy and gastritis-diagnosed patients was found to be a powerful controller of human gastric lipase activity <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=File:Hydrolysis_triacylglycerol_reaction.png&diff=2586217 File:Hydrolysis triacylglycerol reaction.png 2016-04-10T18:52:15Z

<p>Megan M. Roy: Hydrolysis of triacylglycerol.</p> <hr /> <div>Hydrolysis of triacylglycerol.</div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2585982 Sandbox 78 2016-04-09T17:43:21Z

<p>Megan M. Roy: </p> <hr /> <div>==Human Gastric Lipase==<br /> <br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Structure of Human Gastric Lipase (PDB input: 1HLG)' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Hydrophobic and Hydrophilic Regions of Human Gastric Lipase' scene='72/727839/Hydrophobic_and_polar_regions/1' /><br /> <Structure load='1HLG' size='350' frame='true' align='right' caption='Secondary Structure of Human Gastric Lipase' scene='72/727839/Secondary_structure/1' /><br /> <br /> == Introduction ==<br /> <br /> Human gastric lipase (HGL, E.C. 3.1.1.3) (PBD ID: 1hlg) is a type of [[lipase]] (of the enzyme class [[hydrolase]]) that is responsible for initiating the digestion of dietary fats in the stomach <ref name="armand">PMID:7598069</ref>. This enzyme is secreted by the fundic chief cells of the human stomach and catalyzes 10-20% of total lipolytic processes (i.e., those involving fat breakdown) in healthy adults <ref name="armand" />. HGL specifically catalyzes the hydrolysis of triacylglycerol in order to produce diacylglycerol and a carboxylate byproduct <ref name="roussel">PMID:10358049</ref>, a process that facilitates subsequent fat breakdown by pancreatic lipase <ref name="dogs">PMID:20965171</ref>. In terms of disease implications, there is evidence to suggest that HGL secretion is altered in individuals with gastritis <ref name="gastritis">PMID:23899880</ref>.<br /> <br /> == Structural highlights ==<br /> <br /> HGL, a 379 amino acid residue-long lipase enzyme, possesses a catalytic arm consisting of residues Ser-153, His-353, and Asp-324 <ref name="roussel" />. <br /> <br /> == Function ==<br /> <br /> == Relevance to Human Health & Disease ==<br /> <br /> A study was completed to discover the understanding of hormonal regulation of gastric lipase secretion in children and adolescents, as this is still very limited. <br /> <br /> The activity of human gastric lipase was compared among two experimental groups and one control group. The control group included 14 healthy adolescents. The experimental groups were one group of 10 patients diagnosed with ''Helicobacter pylori'' gastritis, and another group of patients exposed to other pathogens besides ''Helicobacter pylori'' to cause gastritis. The activity of human gastric lipase was observed through endoscopic measurements within the collected gastric juice from each patient. The plasma concentrations of glucagon-like peptide-1, cholecystokinin, and glucose-dependent insulinotropic peptide were determined in all patients as well. <br /> <br /> This study suggested that the activity of human gastric lipase activity was changed in patients that were diagnosed with superficial gastritis induced by pathogens other than ''Helicobacter pylori''. The level of activity of human gastric lipase was significantly lower in patients with superficial gastritis than in patients that were healthy (p<0.005) and were diagnosed with ''Helicobacter pylori'' gastritis (p<0.005). The mean levels of glucose-dependent insulinotropic peptide plasma concentrations were lower for patients in the control group (p<0.005) than in non-''Helicobacter pylori'' gastritis and ''Helicobacter pylori'' gastritis patients (p<0.01). The regulation of human gastric lipase secretion by glucagon-like peptide-1 and cholecystokinin was found to be altered in those whom had gastritis. Glucose-dependent insulinotropic peptide in both healthy and gastritis-diagnosed patients was found to be a powerful controller of human gastric lipase activity <ref name="gastritis" />.<br /> <br /> == References ==<br /> <br /> <references/></div>

Megan M. Roy https://proteopedia.org/index.php?title=Sandbox_78&diff=2585981 Sandbox 78 2016-04-09T17:39:46Z

<p>Megan M. Roy: New page: ==Human Gastric Lipase== <StructureSection load='1stp' size='340' side='right' caption='Caption for this structure' scene=''> This is a default text for your page '''Sandbox 78'''. Click a...</p> <hr /> <div>==Human Gastric Lipase==<br /> <StructureSection load='1stp' size='340' side='right' caption='Caption for this structure' scene=''><br /> This is a default text for your page '''Sandbox 78'''. Click above on '''edit this page''' to modify. Be careful with the &lt; and &gt; signs.<br /> You may include any references to papers as in: the use of JSmol in Proteopedia <ref>DOI 10.1002/ijch.201300024</ref> or to the article describing Jmol <ref>PMID:21638687</ref> to the rescue.<br /> <br /> == Function ==<br /> <br /> == Disease ==<br /> <br /> == Relevance ==<br /> <br /> == Structural highlights ==<br /> <br /> This is a sample scene created with SAT to <scene name="/12/3456/Sample/1">color</scene> by Group, and another to make <scene name="/12/3456/Sample/2">a transparent representation</scene> of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.<br /> <br /> </StructureSection><br /> == References ==<br /> <references/></div>

Megan M. Roy