Comparison of the Mitochondrial Membrane Proteins in Rat Liver and Hepatomas

Summary

The mitochondrial membrane proteins isolated from normal rat liver, five hepatoma strains (H35, H35-tc1, H35-tc2, 3924A, and 9098), and tumor-bearing host liver have been compared by polyacrylamide gel electrophoresis. The mitochondrial membranes were isolated from gradient-purified mitochondria by extraction of soluble mitochondrial proteins with the detergent Lubrol WX, and lipid-free proteins were obtained by gel filtration of the membranes solubilized in acidified dimethylformamide. The major protein bands observed with membranes isolated from normal liver and liver from tumor-bearing (H35) rats were identical. A major protein band observed with membranes isolated from normal liver was missing or greatly reduced in membranes isolated from all of the hepatomas. Membranes from hepatoma H35 had a major protein band that was missing or present in very small amounts in membranes from normal liver. This additional band was also observed in lesser amounts in other hepatoma membranes. These changes in electrophoretic patterns suggest alteration of the inner mitochrondrial membrane proteins of hepatoma mitochondria.