Synthesis and identification of benzo[a]pyrene-guanine nucleoside adducts formed by electrochemical oxidation and by horseradish peroxidase catalyzed reaction of benzo[a]pyrene with DNA

One-electron oxidation plays an important role in the metabolism of many substrates and their covalent binding to macromolecules. This mechanism of activation can be demonstrated by elucidation of the structure of DNA adducts. We report the synthesis of adducts by anodic oxidation of benzo(a)pyrene (BP) in the presence of deoxyguanosine (dG) or guanosine (G). By using super(1)H and two-dimensional NMR spectroscopy as well as fast atom bombardment and collisionally activated decomposition (CAD) mass spectrometry, adducts were identified as BP bound at C-6-C-8 of guanine (Gua), dG, and G and to N-7 of Gua.