Blusztajn_1979_Brain.Res_179_319

Choline molecules are needed for the synthesis of acetylcholine and phospholipids in the mammalian brain. An enzymatic activity capable of forming lecithin (phosphatidylcholine) from the step-by-step methylation of phosphatidylethanolamine is identified in the bovine brain. This enzyme(s), phosphatidylethanolamine-N-methyltransferase (EC 2.1.1.17), is localized in the synaptosomal fraction of bovine caudate nucleus, uses S-adenosylmethionine as the methyl donor (apparent Km = 20 micrometers), and has a Vmax of 50--60 pmol/mg protein X h (i.e. about 1% of that found in rat liver). The brain may be able to meet some of its choline requirements by de novo synthesis.