Critical role of sulfhydryl group(s) in ATP-dependent Ca²⁺ sequestration by the plasma membrane fraction from rat liver

The ATP-dependent sequestration of Ca²⁺ by the plasma membrane fraction from rat liver is stimulated by reduced glutathione and dithiothreitol and inhibited by diamide and t-butyl hydroperoxide. The inhibitory effect on Ca²⁺ sequestration by the oxidizing agents is prevented in the presence of the thiols. Our results therefore suggest that free sulfhydryl group(s) may be critical for the activity of hepatic plasma membrane Ca²⁺ translocase, and that inhibition of this activity by the oxidation of such group(s) may contribute to the perturbation of Ca²⁺ homeostasis during oxidative stress.