[Protective role of phospholipids in the enzymatic degradation of mitochondrial membrane proteins].

Composition of phospholipid preparations, isolated from rat liver mitochondria, was studied within various periods of incubation of the organelles obtained including 2 days interval. Distinct decrease in relative content of sphingomyelin, phosphatidyl choline and phosphatidyl ethanolamine was observed in the preparations during the incubation. At the same time, fractions of lysophospholipids and cardiolipin were markedly increased. Studies were carried out on the effect of the phospholipid fractions on hydrolysis of the protein component of mitochondrial membranes by lysosomal hydrolases and pronase. The phospholipids possessed protective functions in the system with the proteinases and mitochondrial membranes. The data obtained suggest that impairment of the phospholipid component appears to precede the proteolysis of proteins in mitochondrial membranes.