phospholipase

An enzyme that catalyzes the hydrolysis of a phospholipid. SYN: lecithinase.

- p. A₁ an enzyme that hydrolyzes a lecithin (1,2-diacylglycerophosphocholine) to a 2-acylglycerophosphocholine and a fatty acid anion.

- p. A₂ an enzyme that catalyzes 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. SYN: lecithinase A, phosphatidase, phosphatidolipase.

- p. B 1. SYN: lysophospholipase. 2. a mixture of p. A₁ and p. A₂.

- p. C Clostridium welchii α-toxin; Clostridium oedematiens β- and γ-toxins; an enzyme that catalyzes the hydrolysis of phosphatidylcholine (and perhaps other phospholipids) to produce choline phosphate and 1,2-diacylglycerol; also acts on sphingomyelin; a key enzyme in the formation of inositol 1,4,5-trisphosphate. SYN: lecithinase C, lipophosphodiesterase I.

- p. D an enzyme that hydrolyzes phosphatidylcholine to produce choline and a phosphatidate; also acts on other phosphatidyl esters. SYN: choline phosphatase, lecithinase D, lipophosphodiesterase II.

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phos·pho·li·pase -'lī-.pās, -.pāz n any of several enzymes that hydrolyze lecithins or phosphatidylethanolamines called also lecithinase

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phos·pho·lip·ase (fos″fo-lipґās) any of a number of enzymes that catalyze the hydrolysis of specific ester bonds in phospholipids. Individual enzymes are grouped on the basis of the bond they hydrolyze and are further categorized as carboxylic acid esterases (p. A₁, p. A₂) or phosphodiesterases (p. C, p. D).