Biochemistry of Polyglycerophosphatides. The Mechanism of Cardiolipin Biosynthesis in Isolated Mitochondria

Abstract

The mechanism of cardiolipin biosynthesis in isolated rat liver mitochondria was studied using endogenously formed and exogenously supplied phosphatidylglycerol-2′-³H in the presence and absence of added Mg²⁺, Mn²⁺, CDP-DL-dioleate, and CDP-D-diglyceride-2-¹⁴C. With endogenously formed and membrane-bound phosphatidylglycerol-2′-³H and in the presence of Mn²⁺, the incorporation of CDP-D-diglyceride-2-¹⁴C into cardiolipin-³H,¹⁴C was demonstrated, establishing the participation of both phosphatidylglycerol-2′-³H and CDP-D-diglyceride-2-¹⁴C in the formation of cardiolipin-³H,¹⁴C. In addition, the release of water-soluble labeled compounds was measured and the efficiency of glycerol-2-³H recovery after the incubation with mitochondria was determined. It was concluded that under the described experimental conditions the formation of cardiolipin in isolated mitochondria takes place according to the reaction mechanism: phosphatidylglycerol + CDP-diglyceride → cardiolipin. Some aspects of these findings are discussed in detail