1-alkyl-2-lyso-sn-glycero-3-phosphate acetyltransferase

Publisher Summary The first step in the de novo pathway of platelet-activating factor (PAF) biosynthesis is catalyzed by acetyl-CoA:1-alkyl-2-lyso- sn -glycero-3-phosphate acetyltransferase. This initial reaction involves the acetylation of the O -alkyl analog of lysophosphatidic acid, a key branch point in the ether lipid pathway as this lyso compound can also be acylated by a long-chain acyl-CoA acyltransferase. The 1-alkyl-2-lyso- sn -glycero-3-phosphate branch point is introduced after alkyldihydroxyacetonephosphate (a product of alkyI-DHAP synthase) is reduced by an NADPH:alkyldihydroxyacetonephosphate oxidoreductase. 1-Alkyl-2-acetyl- sn -glycero-3-phosphate, the product of acetylation reaction, can then be converted to PAF in two sequential reactions catalyzed by a phosphatase and a cholinephosphotransferase. 1-Alkyl-2-acetyl- sn -glycerols formed by the phosphatase is an important end product rather than just an intermediate in the de novo pathway as this alkyl analog of a diglyceride also influences responses involving protein kinase C activation and induces cell differentiation. The chapter provides a concise description of the method for assaying the de novo acetyltransferase and summarizes its properties.