The role of membrane structure in the activation of mitochondrial phospholipases. 1. Activation of mitochondrial phospholipases by lipid peroxidation products.

Induction of lipid peroxidation is shown to alter the structure of mitochondrial membrane and to activate endogenous phospholipases A2, C, D, and lysophospholipase A. Fe(2+)-, cumene hydroperoxide- and ultraviolet-induced lipid peroxidation results in the activation of mitochondrial phospholipases.

The role of membrane structure in activation of mitochondrial phospholipases. 2. Mechanism of crambin action on the activities of mitochondrial membrane phospholipases and microviscosity.

Effects of crambin on the phospholipase activity, lipid peroxidation and structure of mitochondrial membranes have been investigated. Crambin has been shown to inhibit lipid peroxidation and phospholipase activity induced by Ca2+ and freezing-thawing of mitochondria. As shown by ESR studies, these effects are based on the ability of crambin to cause changes in mitochondrial membrane structure.