Isolation and characterization of rat liver cytosolic aldehyde dehydrogenases induced by phenanthrene or benzo[a]pyrene

Abstract 1. 1. The cytosolic aldehyde dehydrogenase was isolated from the liver of Wistar rats treated with phenanthrene (non-carcinogenic) or benzo[ a ]pyrene (carcinogenic polycyclic aromatic hydrocarbon). 2. 2. The benzo[ a ]pyrene-induced enzyme has higher K m values for small aliphatic aldehydes and a lower molecular weight than the phenanthrene-induced enzyme. 3. 3. It is more resistant to changes of pH and to inhibition by disulfiram, but more sensitive to heat denaturation than the phenanthrene-induced enzyme. 4. 4. The phenanthrene-induced aldehyde dehydrogenase is very similar to the normal uninduced aldehyde dehydrogenase, whereas the benzo[ a ]pyrene-induced aldehyde dehydrogenase has common properties with the TCDD (2,3,7,8-tetrachlorodibenzo- p -dioxin)-induced enzyme and the hepatoma-specific enzyme.