A BLEOMYCIN-INACTIVATING ENZYME IN MOUSE LIVER

Abstract

Affinity chromatography of a bleomycin-inactivating enzyme was studied on Sepharose 4 B-bleomycin A₅ and Sepharose 4 B-lysinamide. Mouse liver was homogenized, and the enzyme extracted by ammonium sulfate precipitation and Sephadex G-200 chromatography. Affinity chromatography of the extract on Sepharose 4 B-lysinamide gave 25-fold purified enzyme, Further purification vas not successful because of instability of the enzyme. It hydrolyzed L-lysinamide, L-lysyl-β-naphthyl-amide, L-arginy1-β-naphthylamide, L-lysyl-L-lysine and Iysyl-bradykinin, but not leucinamide or L-leucyl-β-naphthylamide. Hydrolysis of L-lysyl-β-naphthylamide and L-arginyl-β-naphthylamide by the enzyme was competitively inhibited by bleomycin B₂. The bleomycin-inactivating enzyme of rat liver was separated from a known aminopeptidase B.