| phospholipase A1 | <enzyme> An enzyme that hydrolyzes a lecithin (1,2-diacylglycerophosphocholine) to a 2-acylglycerophosphocholine and a fatty acid anion. (05 Mar 2000) |
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| phospholipase | <enzyme> That hydrolyse ester bonds in phospholipids. They comprise two types: aliphatic esterases (phospholipase A1, A2 and B) that release fatty acids and phosphodiesterases (types C and D) that release diacyl glycerol or phosphatidic acid respectively. Type A2 is widely distributed in venoms and digestive secretions. Types A1, A2 and C the latter specific for phosphatidyl inositol) are present in all mammalian tissues. Type C is also found as a highly toxic secretion product of pathogenic bacteria. Type B attacks monoacyl phospholipids and is poorly characterised. Type D is largely of plant origin. PLA2 Type II (a secreted enzyme, but not the same as the Type I digestive pancreatic enzyme) is probably very important in inflammation because its action can release arachidonic acid, the starting point for eicosanoid synthesis. Phosphatidyl inositol bisphosphate specific phospholipase C is important in generating diacyl glycerol and inositol trisphosphate, both second messengers. (31 Dec 1997) |
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| phospholipase A2 | <enzyme> An enzyme that catalyses the hydrolysis of a lecithin to a lysolecithin by removing the 2-acyl group; also acts on other phospholipids by removing a fatty acid from the 2-position; this enzyme has an important role in prostaglandin and leukotriene biosynthesis. Synonym: lecithinase A, phosphatidase, phosphatidolipase. (05 Mar 2000) |
| phospholipase B | There are reports that phospholipase B is a mixture of phospholipase A1 and phospholipase A2. See: lysophospholipase. (05 Mar 2000) |
| phospholipase c | <enzyme> An enzyme found in the alpha-toxin of clostridium welchii and other strains of clostridia and bacilli. It hydrolyzes glycerophosphatidates with the formation of 1,2-diacylglycerol and a phosphorylated nitrogenous base such as choline. Chemical name: Phosphatidylcholine cholinephosphohydrolase Registry number: EC 3.1.4.3 (12 Dec 1998) |
| phospholipase d | <enzyme> An enzyme found mostly in plant tissue. It hydrolyzes glycerophosphatidates with the formation of a phosphatidic acid and a nitrogenous base such as choline. This enzyme also catalyses transphosphatidylation reactions. Chemical name: Phosphatidylcholine phosphatidohydrolase Registry number: EC 3.1.4.4 (12 Dec 1998) |