Modification of the biosynthesis and composition of polyglycerophosphatides in outer and inner mitochondrial membranes by cytidine liponucleotides

The biosynthesis of 3H]polyglycerophosphatides (3H]phosphatidylglycerophosphate and 3H]phosphatidylglycerol) in mitochondrial and submitochondrial (outer and inner) membranes isolated from guinea pig liver was examined. Experimental results have established that the amount of biosynthesized 3H]polyglycerophosphatides and the relative amounts of biosynthesized 3H]phosphatidylglycerol and 3H]phosphatidylglycerolphosphate can be influenced by varying the composition of fatty acids in CDP-diglycerides and by altering the incubation time of the mixture containing CDP-diglycerides (obligatory precursor), sn-2-3H]glycerol-3-phosphate and mitochondria or submitochondrial membranes. The changes thus obtained in respect to the amount and composition of biosynthesized 3H]polyglycerophosphatides are different in mitochondria and submitochondrial membranes. The highest amount of biosynthesized 3H]polyglycerophosphatides was obtained with CDP-didecanoin and inner mitochondrial membranes. The greatest accumulation of 3H]phosphatidylglycerol with CDP-didecanoin was obtained in mitochondria and outer mitochondrial membranes, while in inner mitochondrial membranes the amounts of 3H]phosphatidylglycerol and 3H]phosphatidylglycerolphosphate accumulated were approximately the same. In general, prolongation of the incubation time decreased the relative amounts of 3H]phosphatidylglycerolphosphate and increased the amount of accumulated 3H]phosphatidylglycerol, but the absolute amounts of these 3H]polyglycerophosphatides were more dependent on fatty acid composition of CDP-diglycerides tested. The following cytidine liponucleotides were tested: CDP-didecanoin, CDP-dipalmitin, CDP-diolein, and CDP-diglycerides containing saturated and unsaturated fatty acids similar to those in egg yolk lecithin. The formation of 3H]cardiolipin from 3H]phosphatidylglycerol in the presence of CDP-didecanoin and Mn2+ was found in both the outer and inner mitochondrial membranes.