Generation of the precursor (lyso-PAF) of platelet-activating factor via a CoA-dependent transacylase.
The microsomal fraction from rat spleen was shown to possess a CoA-dependent transacylase activity that produced 1-[3H]alkyl-2-lyso-sn-glycero-3-phosphocholine ([3H]lyso-PAF), the immediate precursor of PAF in the remodeling pathway of biosynthesis, from 1-[3H]alkyl-2-acyl-sn-glycero-3-phosphocholine. This CoA-dependent transacylase did not require ATP or metal ions for activity making it unlikely that either acyl-CoA-synthetase or a Ca(2+)-dependent phospholipase A2 were involved in the generation of [3H]lyso-PAF. Albumin, in addition to CoA, was required to demonstrate the formation of [3H]lyso-PAF from 1-[3H]alkyl-2-acyl-sn-glycero-3-phosphocholine. It appeared that a major function of albumin in the incubations was to complex the [3H]lyso-PAF formed, thus removing this end-product from the reaction.
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Medical Sciences Division, Oak Ridge Associated Universities, Tennessee 37831-0117, USA.
Fitzgerald
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Smith
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Snyder
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D008243:1-Acylglycerophosphocholine O-Acyltransferase / Q000378:metabolism*; D000217:Acyltransferases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003065:Coenzyme A / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000201:enzymology*; D010972:Platelet Activating Factor / Q000031:analogs & derivatives* / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013154:Spleen / Q000201:enzymology*; D013379:Substrate Specificity
C029271:O-deacetyl platelet activating factor; D010972:Platelet Activating Factor; D012710:Serum Albumin, Bovine; D000255:Adenosine Triphosphate; D000217:Acyltransferases; C039766:arachidonyl transacylase; D008243:1-Acylglycerophosphocholine O-Acyltransferase; D003065:Coenzyme A