The biosynthesis of choline and its relation to phospholipid metabolism.

摘要: The biosynthesis of choline has been studied in the rat with [3-14C]serine, [1,2-14C]-aminoethanol and [14CH3]methionine as precursors. When [14C]aminoethanol was given to intact rats, radioactive isolated from liver phospholipids, but no phosphocholine found an aqueous extract. When [14C]methionine given, mono- dimethylaminoethanol, well choline, were phospholipids. dimethylaminoethanol had much higher turnover rates than choline. administered, incorporation radioactivity into phospholipid delayed. In vitro experiments showed that choline-labeled lecithin formed when rat-liver microsomes incubated S-adenosylmethionine. When [14C]serine injected aminoethanol labeled both hydroxyethyl- methyl groups, isolated. Turnover specific activity studies phosphoaminoethanol cytidinediphosphoaminoethanol are unlikely intermediates formation serine. On basis these results it is concluded phosphatidylserine decarboxylated phosphatidylaminoethanol latter compounds methylated form lecithin. In this reaction all groups incorporated by transmethylation S-adenosylmethionine. The significance discussed relation fat metabolism.