The formation of BPDE occurs through the metabolic activation of benzo[a]pyrene. Initially, benzo[a]pyrene is oxidized by cytochrome P450 enzymes to form benzo[a]pyrene-7,8-epoxide. This intermediate is further hydrolyzed by epoxide hydrolase to produce anti-benzo[a]pyrene-7,8-dihydrodiol. Finally, another round of oxidation by cytochrome P450 converts the dihydrodiol to BPDE.
