Preparation of radioactively labeled synthetic sn-1,2-diacylglycerols for studies of lipid metabolism.

A method was developed for the synthesis of stereo-specific sn-1,2-diacylglycerols radioactively labeled on the glycerol backbone. This method includes the acylation of L-[U-14C]glycerol 3-phosphate with fatty acid anhydrides in the presence of dimethylaminopyridine and the tetraethylammonium salt of the fatty acid used for the acylation. The phosphatidic acid obtained from this synthesis was converted to sn-1,2-diacyl[U-14C]glycerol by the action of phospholipase C. When di10:0-, di-18:1-, di-18:2-, and di-22:1-diacyl[U-14C]glycerols made by this method were provided as substrates to microsome preparations from developing cotyledons of safflower (Carthamus tinctorius), they were all incorporated into phosphatidylcholine by the action of cholinephosphotransferase. The time course of the incorporation into phosphatidylcholine showed no differences for these four substrates and the initial rates were comparable.