Damage to microsomal membrane by lipid peroxidation

Abstract

Abstract Alterations of microsomal membrane integrity were examined during lipid peroxidation. Loss of membrane‐bound NADPH cytochrome c reductase activity and protein release into the aqueous phase were related to disruption of the lipophilic region of the membrane. Formation of fluorescent products in the lipid phase of the membrane occurred only in the presence of peroxidation products. Changes in the membrane lipid phase during peroxidation included a decrease in the reactive amino groups of the phospholipids and a decrease in detectable phosphatidyl ethanolamine. In an ultrafiltration continuous flow chamber, peroxidized microsomal membranes were hydrolyzed to a lesser degree by solubilized lysosomal cathepsins and to a greater degree by lysosomal nucleases than were nonperoxidized membranes.