Xanthine oxidase-catalyzed DNA binding of dihydrodiol derivatives of nitro-polycyclic aromatic hydrocarbons.

Xanthine oxidase, a mammalian nitroreductase, catalyzed the covalent binding of a series of nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) trans-dihydrodiols to DNA. Some of the trans-dihydrodiols bound to DNA to a greater extent than their parent nitro-PAHs; however, when the dihydrodiol moiety was peri to the nitro substituent low levels of binding were observed. These data illustrate that ring-oxidation and hydrolysis of nitro-PAHs to their trans-dihydrodiols followed by nitroreduction is a potential metabolic pathway leading to DNA adducts in mammals.