Significance of Posttranslational Modification of Drug Metabolizing Enzymes by Phosphorylation for the Control of Carcinogenic Metabolites

The total activity of foreign compound metabolizing enzymes may change by altering the amount or the specific activity of the enzyme by induction or repression, or by activation or inhibition. The important contribution of enzyme induction is well known (Conney 1982, Oesch 1986, Nebert and Jones 1989). This is a relatively slow process which requires the biosynthesis of the enzyme protein. The possibility of a faster regulation of foreign compound metabolism by posttranslational modification by phosphorylation of an already preexisting protein molecule has only recently received attention. A central role in the metabolism of foreign compounds is played by the cytochrome P450-dependent monoo…