Benzo(a)pyrene metabolites formed by the action of yeast cytochrome P-450/P-448

Benzo(a)pyrene metabolites have been identified by high-pressure liquid chromatography after production by a cytochrome P-450 in brewer's yeast disruptates. The major metabolites are 7,8-dihydro-7,8-dihydroxy-benzo(a)pyrene, 9-hydroxybenzo(a)-pyrene and 3-hydroxybenzo(a)pyrene. Pretreatment of the yeast with benzo(a)-pyrene, during its growth decreases the Michaelis constant (K_m) of the enzyme for benzo(a)pyrene, using either NADPH or cumene hydroperoxide as a cofactor.