FIG. 1.
Metabolism of VCH and DMBA. (A) VCH is bioactivated by CYP450 isoforms to form either 1,2- or 7,8-monoepoxide (VCM) metabolites and, subsequently, VCD. The action of mEH metabolizes VCD to an inactive tetrol metabolite. Adapted from Keller et al. (1997). (B) DMBA is bioactivated by CYP450 isoforms to a DMBA-3,4-epoxide and, subsequently, hydrolyzed by mEH to DMBA-3,4-diol. Further activation by CYP450 isoforms results in formation of the bioactive metabolite, DMBA-3,4-diol-1,2-epoxide. Adapted from Miyata et al. (1999).