Scheme 1. Metabolic activation of 4-aminobiphenyl and aristolochic acid I and DNA adduct formation.
The bioactivation of 4-ABP by cytochrome P450 (P450) and the bioactivation of AA-I occurs by several enzymes, including P450 or NAD(P)H dehydrogenase [quinone] 1. N-acetylransferases (NATs) or sulfotransferases activate the hydroxylamine metabolites to reactive intermediates that bind to DNA.