ACYLATION OF ISOMERIC MONOACYL PHOSPHATIDYLCHOLINES

1. 1. A comparison has been made of 1-acyl-3-sn-phosphatidylcholine and 2-acyl-3-sn-phosphatidylcholine as acyl acceptors in the synthesis of phosphatidylcholine as catalysed by acyl-CoA: monoacylphosphatidylcholine acyltransferase. With 1-acyl-3-sn-GPC, the following pattern for the extent of acyl transfer was observed: oleate > linoleate > laurate > palmitate ≥ stearate. With 2-acyl-3-sn-GPC as acceptor, this sequence was: stearate > palmitate > laurate ≥ oleate > linoleate. 2. 2. The conversion of 1-[1-su14,C]palmitoyl-sn-glycero-3-phosphorylcholine and 2-[9,10-3H2]stearoyl-sn-glycero-3-phosphorylcholine into molecular species of 3-sn-phosphatidylcholine has been shown to be in accordance with the view that 1-acyl-3-sn-GPC is preferentially acylated with unsaturated acids, whereas 2-acyl-3-sn-GPC is better acylated with saturated acids. The labelled acyl constituents were recovered in the synthesized 3-sn-phosphatidylcholines at essentially the same positions as those at which they were originally located in the substrates. 3. 3. Monoacyl phosphatidylcholine, which was derived from sn-glycero-1-phosphoric acid, has been shown not to act as substrate for the acyl-CoA: monoacylphosphatidylcholine acyltransferases from rat liver microsomes. © 1968.