Some properties and electrophoretic patterns of rat liver esterases in relation to hepatocarcinogenesis by 3'-methyl-4-(dimethylamino) azobenzene.

Five distinctly different types of naphthyl acetate esterase in rat liver were examined for study of liver enzymes during hepatocarcinogenesis. Three types of esterase in normal adult liver were separated by column chromatography. Main esterase in adult hepatocytes, which was demonstrated near the origin in cellulose acetate electrophoresis, was very sensitive to diisopropyl phosphorofluoridate (DFP). The other two esterases showed different electrophoretic mobility, while their Km values did not differ and both were considerably resistant to DFP. An anodic minor component in normal adult liver, which had a characteristic esterase pattern of infant liver, increased in the liver of rats fed 3'-methyl-4-(dimethylamino) azobenzene. This esterase was obtained by electrophoresis on Cellogel block. It was partially inhibited by DFP and p-chloromercuribenzoate, activated by cysteine, and showed a different Km value from the above esterases. Another minor component situated at the most cathodic side, which had characteristic esterase patterns of fetal liver and hepatoma, was very sensitive to DFP and eserine, and showed a characteristic of nonspecific cholinesterase as proved by staining.