A protein inhibitor of hepatic drug metabolizing enzymes from Ehrlich ascites cells

Hepatic drug metabolizing enzymes were significantly decreased in Ehrlich ascites tumour-bearing mice. A protein inhibitor of hepatic drug metabolizing enzymes was isolated from Ehrlich ascites cells and purified. This involved ammonium sulphate fractionation (60–80%), DEAE, phosphocellulose, Sephadex G-100 and hydroxyapatite column chromatography. Purification attained was 800-fold. The inhibitory protein was effective in decreasing all the components of hepatic mixed-functionoxidase system and drug metabolizing enzymes both in vivo and in vitro. This novel inhibitor may have potential applications in chemical carcinogenesis.