Biosynthesis of bis(monoacylglyceryl)phosphate and acylphosphatidylglycerol in rat liver mitochondrial.

Abstract

Bis(monoacylglyceryl)phosphate is present in trace quantities in normal liver where it represents smaller than 1 percent of total liver phospholipids. This compound is of considerable interest since its level can be greatly increased in certain lipidoses, either of a genetic nature or caused by drugs. Biosynthesis of bis(monoacylglyceryl)P in vitro has not previously been demonstrated. This paper reports the enzymatic formation of bis(monoacylglyceryl)P and acylphosphatidylglycerol as minor products from cytidine diphosphate diglyceride and radioactive sn-glycerol-3-P using a crude mitochondrial fraction from normal rat liver; phosphatidylglycerol was the principal product. Evidence is also presented which shows the enzymatic formation of acylphosphatidylglycerol and bis(monoacylglyceryl)P from [1',3'-14C]phosphatidylglycerol by a crude rat liver mitochondrial preparation in vitro. The structures of the radioactive bis(monoacylglyceryl)P and acylphosphatidylglycerol were tentatively established by thin layer chromatography, and chromatography of the products of mild alkaline hydrolysis and acetolysis. Radioactive acylphosphatidylglycerol was stoichiometrically converted to bis(monoacylglyceryl)P by treatment with bee venom phospholipase A, providing additional evidence for the structure of acylphosphatidylglycerol and bis(monoacylglyceryl)P.