Synthesis of 1-palmitoyl and 1-stearoyl phosphatidylcholines from mixtures of acyl acceptors via acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase in liver microsomes.
The fatty acid selectivity of the acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase in rat liver microsomes was studied using a mixture of the [1-(3)H]palmitoyl plus [1-(14C)stearoyl molecular species of 1-acylglyceryl-phosphorylcholine. At a 1-acyl-sn-glycero-3-phosphorylcholine concentration of 0.16 mM, the enzyme exhibited a selectivity of 3.5-fold for the 1-palmitoyl over the 1-stearoyl species of the acyl acceptor and reaction velocities with linoleoyl- and arachidonoyl-CoA were 38--47% greater than with oleoyl-CoA. Lowering the acceptor concentration to 0.016 mM gave reaction rates with the polyenoic thiolesters which were 174--187% greater than with oleoyl-CoA and the 1-palmitoyl-sn-glycero-3-phosphorylcholine was preferred by 2.2, 1.6, and 1.6-fold with oleoyl-, linoleoyl- and arachidonoyl-CoA, respectively. The results support the potential importance of the fatty acid selectivities of the acyl-CoA:1-acyl-sn-glycero-3-phosphorylcholine acyltransferase towards both acyl acceptor and donor in regulating the phosphatidylcholine species formed by the reaction in vivo.
D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000378:metabolism*; D000214:Acyl Coenzyme A / Q000378:metabolism*; D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D008041:Linoleic Acids / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000378:metabolism; D008862:Microsomes, Liver / Q000378:metabolism*; D009829:Oleic Acids / Q000378:metabolism; D010169:Palmitic Acids / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D051381:Rats; D013229:Stearic Acids / Q000378:metabolism*
D000214:Acyl Coenzyme A; D001095:Arachidonic Acids; D008041:Linoleic Acids; D008244:Lysophosphatidylcholines; D009829:Oleic Acids; D010169:Palmitic Acids; D010713:Phosphatidylcholines; D011506:Proteins; D013229:Stearic Acids; D000217:Acyltransferases; D008243:1-Acylglycerophosphocholine O-Acyltransferase