title: Modulation of diacylglycerol acyltransferase by lysophosphatidylcholine and related monochain phospholipids.
abstract: Acyl-CoA : 1,2-diacylglycerol O-acyltransferase (EC 2.3.1.20) activity of rat liver microsomes was found to be stimulated by 1-acyl-sn-glycero-3-phosphocholine at low concentrations, but was inhibited above 0.2 mM. Diacylglycerol acylation was optimal at 75 microM lysophosphatidylcholine, resulting in a more than 2-fold activation of the enzyme. Acyltransferase activity disappeared above 0.5 mM lysophosphatidylcholine levels. 0.05% sodium taurocholate supplementation reduced diacylglycerol acyltransferase activity by approx. 2/3 over the entire range of lysophosphatidylcholine concentrations. 1-O-Hexadecylpropanediol-3-phosphocholine was shown to mimic lysophosphatidylcholine at stimulatory and at inhibitory concentrations in the absence and in the presence of sodium taurocholate, thus ruling out acyl-CoA depletion due to lysophosphatidylcholine acylation as a cause of depressed triacylglycerol synthesis at higher lysophosphatidylcholine levels. 1-Acyl-sn-glycero-3-phosphoethanolamine stimulated diacylglycerol acyltransferase to a lesser extent, without showing inhibition at higher concentrations. The data point towards a direct effect of the lysophospholipids on the acyltransferase system.
mesh_terms: D000217:Acyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D051048:Diacylglycerol O-Acyltransferase; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005997:Glycerylphosphorylcholine / Q000031:analogs & derivatives / Q000494:pharmacology; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D051381:Rats; D013656:Taurocholic Acid / Q000494:pharmacology
chemical_list: C014307:1-acylglycerylphosphorylcholine; D008244:Lysophosphatidylcholines; D013656:Taurocholic Acid; D005997:Glycerylphosphorylcholine; D000217:Acyltransferases; D051048:Diacylglycerol O-Acyltransferase