Figure 1.
Proposed pathways of biotransformation and DNA adduct formation of BaP catalyzed by P450 1A1 and mEH. Upper panel: the typical three-step activation process by P450 1A1 followed by hydrolysis by mEH leads to BPDE which forms dG-N2-BPDE (adduct 1). Lower panel: the two-step activation process by P450 1A1 leads to the formation of 9-hydroxy-BaP-4,5-epoxide that can react with deoxyguanosine in DNA (adduct 2). Insert: Autoradiographic profile of BaP-DNA adducts formed by human P450 1A1 in Supersomes with mEH in the presence of NADH and cytochrome b5 as evaluated by TLC 32P-postlabeling as described previously.19