Acylation of 2-acyl-glycerophosphocholine in guinea-pig heart microsomal fractions.
Acyl-CoA:2-acyl-sn-glycero-3-phosphocholine (GPC) acyltransferase is required for the maintenance of the asymmetric distribution of saturated fatty acids at the C-1 position of phosphatidylcholine; however, this activity has been reported to be absent in cardiac tissue. In the present study a very active acyl-CoA:2-acyl-GPC activity was detected and characterized in guinea-pig heart microsomes (microsomal fractions); the mitochondria did not appear to possess this activity. The acyl-CoA specificity of the microsomal acyl-CoA:2-acyl-GPC acyltransferase was distinct from the corresponding acyl-CoA:1-acyl-GPC acyltransferase. These differences were due to the position of the fatty acid on the lysophospholipid rather than the composition of the fatty acids. The enzyme did not exhibit a distinct preference for saturated fatty acids, as might be expected. Our results suggest that, in the heart, control of the intracellular composition and concentration of acyl-CoAs by acyl-CoA hydrolase and acyl-CoA synthetase may play an important role in maintaining the asymmetric distribution of fatty acids in phosphatidylcholine.
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
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Arthur
D000215:Acylation; D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D006168:Guinea Pigs; D008861:Microsomes / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology*
D000217:Acyltransferases; C031076:2-acylglycerophosphocholine acyltransferase