Biochemistry of polyglycerophosphatides in central nervous tissue. I. On the biosynthesis, structure, and enzymatic degradation of phosphatidylglycerophosphate and phosphatidylglycerol in isolated sheep brain mitochondria

Abstract

The formation of labelled phosphatidylglycerophosphate and phosphatidylglycerol from L-glycero-3-phosphate-2-3H and cytidine diphosphate (CDP)-D-diglyceride in subcellular particles of sheep brain has been studied, establishing the predominant location of this enzyme system in mitochondria. The general characteristics and the optimal conditions for the biosynthesis of these lipids have been determined and the chromatographic separation and isolation of phosphatidylglycerophosphate and phosphatidylglycerol are described. In addition, the chemical and enzymatic degradations supporting the structure and configuration for each biosynthesized lipid are presented. The enzymatic dephosphorylation of phosphatiadylglycerophosphate to phosphatidylglycerol with mitochondria isolated from sheep brain has been found. No biosynthesized cardiolipin was, however, detected.The mechanism of the enzymatic reactions for the formation of these lipids has been studied by using L-glycero-3-phosphate[33P]-2-3H and CDP-D-diglyceride; the pathway found by Kennedy et al. (1) for the biosynthesis of phosphatidylglycerol in liver is applicable in the biosynthesis of this compound in sheep brain mitochondria.