| phosphoglycerides | Acylglycerol and diacylglycerol phosphates;constituents of nerve tissue, and involved in fat transport and storage. (05 Mar 2000) |
|---|---|
| phosphoglyceromutase | An isomerizing enzyme catalyzing the reversible interconversion of 2-phosphoglycerate and 3-phosphoglycerate with 2,3-bisphosphoglycerate present as a cofactor; a deficiency of this enzyme, which plays a role in glycolysis, is an inherited disorder that results in an intolerance for strenuous exercise. (05 Mar 2000) |
| phosphoheptose isomerase | <enzyme> Sedoheptulose-7-p is converted to d-glycero-d-manno-heptulose Registry number: EC 5.3.1.- (26 Jun 1999) |
| phosphohexokinase | <enzyme> An enzyme that catalyses the conversion of a nucleotide triphosphate and a sugar phosphate to a nucleotide diphosphate and a sugar diphosphate. D-fructose 6-phosphate, d-tagatose 6-phosphate, and sedoheptulose 7-phosphate can act as acceptors; ATP, utp, ctp, and itp can act as donors. A deficiency of this enzyme is the cause of glycogen storage disease type vii. Chemical name: ATP:D-fructose-6-phosphate 6-phosphotransferase Registry number: EC 2.7.1.11 (12 Dec 1998) |
| phosphohexomutase | <enzyme> An enzyme that catalyses the reversible interconversion of d-fructose 6-phosphate and d-glucose-6-phosphate; a part of glycolysis and gluconeogenesis; glucosephosphate isomerase deficiency is an inherited disorder resulting in liver glycogenesis and haemolytic anaemia. Synonym: hexosephosphate isomerase, phosphohexomutase, phosphohexose isomerase. (05 Mar 2000) |
| phosphohexose isomerase | <enzyme> An enzyme that catalyses the reversible interconversion of d-fructose 6-phosphate and d-glucose-6-phosphate; a part of glycolysis and gluconeogenesis; glucosephosphate isomerase deficiency is an inherited disorder resulting in liver glycogenesis and haemolytic anaemia. Synonym: hexosephosphate isomerase, phosphohexomutase, phosphohexose isomerase. (05 Mar 2000) |
| phosphohexose isomerase deficiency | <enzyme> An enzyme deficiency characterised by chronic nonspherocytic haemolytic anaemia; autosomal recessive inheritance. Synonym: phosphohexose isomerase deficiency. (05 Mar 2000) |
| phosphohydrolases | Phosphoric monoester hydrolases;enzymes (EC sub-subclass 3.1.3) cleaving phosphoric acid (as orthophosphate) from its esters; trivial names usually end in phosphate. (05 Mar 2000) |
| phosphoinositide | <biochemistry> A phosphatidic acid combined with inositol found in biomembranes and a precursor to certain cellular signals. Sometimes referred to as inositide. It is a very important minor phospholipid in eukaryotes, involved in signal transduction processes. Contains myo inositol linked through the 1 hydroxyl group to phosphatidic acid. The 4 phosphate (PIP) and 4, 5 bisphosphate derivatives PIP2) are formed and broken down in membranes by the action of specific kinases and phosphatases (futile cycles). Signal sensitive phospholipase C enzymes remove the inositol moiety, in particular from 1,4,5 trisphosphate (PIP2) as inositol 1,4,5 triphosphate (Ins P3: IP3). Both the diacyl glycerol and products act as second messengers. Synonym: phosphoinositide. (20 Sep 2002) |
| phosphokinase | A phosphotransferase or a kinase. (05 Mar 2000) |
| phospholamban kinase | <enzyme> A delta-cam kinase isozyme; catalyses the phosphorylation of phospholamban Registry number: EC 2.7.1.- Synonym: phospholamban sarcoplasmic reticulum calmodulin-dependent protein kinase, phospholamban srcam kinase (26 Jun 1999) |
| phospholamban phosphatase | <enzyme> Purified from canine cardiac cytosol; dephosphorylates pholamban; stimulated by mg+2, mn+2 or ca+2 Registry number: EC 3.1.3.- (26 Jun 1999) |
| 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) |
| phospholipase A1 | <enzyme> An enzyme that hydrolyzes a lecithin (1,2-diacylglycerophosphocholine) to a 2-acylglycerophosphocholine and a fatty acid anion. (05 Mar 2000) |
| 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) |