Effect of lipid autoperoxidation on the activity of the sarcoplasmic reticulum (Ca2+-Mg2+)ATPase reconstituted into egg yolk phosphatidylcholine bilayers.

Abstract

The activity of (Ca(2+)-Mg2+)ATPase reconstituted into egg yolk phosphatidylcholine liposomes is reduced when the lipid has been oxidized before the reconstitution procedure. It is suggested that the reversible decrease in activity is caused by a decrease of the lipid bilayer thickness due to the shortening of lipid acyl chains during autoperoxidation; the irreversible decrease in the activity is caused by chemical reactions of the enzyme SH groups with the lipid autoperoxidation products.