- (2-Hydroxyethyl)trimethylammonium ion; found in most animal tissues either free or in combination as lecithin (phosphatidylcholine), acetate (acetylcholine), or cytidine diphosphate (cytidine diphosphocholine). It is included in the vitamin B complex; as acetylcholine (c. esterified with acetic acid), it is essential for synaptic transmission. Several salts of c. are used in medicine. SYN: lipotropic factor, transmethylation factor.- c. acetyltransferase an enzyme catalyzing the condensation of c. and acetyl-coenzyme A, forming O-acetylcholine and coenzyme A. SYN: c. acetylase.- activated c. SYN: cytidine diphosphocholine.- c. kinase an enzyme that catalyzes the formation of O-phosphocholine and ADP from c. and ATP. SYN: c. phosphokinase.- c. phosphate cytidylyltransferase an enzyme that catalyzes a key step in lecithin biosynthesis : CTP + phosphocholine ⇄ pyrophosphate + CDP-c..- c. salicylate c. salt of salicyclic acid, an analgesic and antipyretic (because of the salicylate moiety).- c. theophyllinate SYN: oxtriphylline.
* * *cho·line 'kō-.lēn n a basic compound C5H15NO2 that is found in various foods (as egg yolk and legumes) or is synthesized in the liver and that is a component of lecithin, is a precursor of acetylcholine, and is essential to liver function
* * *n.a basic compound important in the synthesis of phosphatidylcholine (lecithin) and other phospholipid and of acetylcholine. It is also involved in the transport of fat in the body. Choline is sometimes classed as a vitamin but, although it is essential for life, it can be synthesized in the body.
* * *cho·line (koґlēn) a water-soluble compound derivable from many animal and some vegetable tissues and produced synthetically. Although it can be synthesized by humans, it is often included in the vitamin B complex (q.v.). It is the basic constituent of lecithin and prevents the deposition of fat in the liver; the acetic acid ester of choline (acetylcholine) is essential in synaptic transmission of nerve impulses. Choline is also oxidized to form betaine in methionine biosynthesis.
Medical dictionary. 2011.