| phosphatidylcholine | <biochemistry> The major phospholipid of most mammalian cell membranes where the 1 acyl residue is normally saturated and the 2 acyl residue unsaturated. Choline is attached to phosphatidic acid by a phosphodiester linkage. Major synthetic route is from diacyl glycerol and CDP choline. Forms monolayers at an air water interface and forms bilayer structures (liposomes) if dispersed in aqueous medium. A zwitterion over a wide pH range. Readily hydrolysed in dilute alkali. (31 Dec 1997) |
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| phosphatidylcholine-ceramide phosphocholine transferase | <enzyme> Cdpcholine is not a donor; imvolved in sphingomyelin synthesis Registry number: EC 2.7.8.- Synonym: pc-cer-pch transferase, sphingomyelin synthase (26 Jun 1999) |
| phosphatidylcholine-sterol o-acyltransferase | <enzyme> An enzyme secreted from the liver into the plasma of many mammalian species. It catalyses the esterification of the hydroxyl group of lipoprotein cholesterol by the transfer of a fatty acid from the c-2 position of lecithin. In familial lecithin:cholesterol acyltransferase deficiency disease, the absence of the enzyme results in an excess of unesterified cholesterol in plasma. Chemical name: Phosphatidylcholine:sterol O-acyltransferase Registry number: EC 2.3.1.43 (12 Dec 1998) |
| phosphatidylcholines | <biochemistry> Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids. (12 Dec 1998) |