Detection of 3'-hydroxy-1,N6-benzetheno-2'-deoxyadenosine 3'-phosphate by 32P postlabeling of DNA reacted with p-benzoquinone.

2'-Deoxyadenosine 3'-phosphate was reacted with a mixture of p-benzoquinone (p-BQ) and hydroquinone in aqueous medium at pH 6, and the main product was isolated and characterized by 1H NMR spectroscopy, liquid secondary ion mass spectroscopy (LSIMS), and high-resolution direct chemical ionization mass spectroscopy (HRDCIMS). The structure of this covalent adduct was assigned as 3'-hydroxy-1,N6-benzetheno-2'-deoxyadenosine 3'-phosphate. Reaction of DNA with p-BQ produced three major adducts as detected by 32P postlabeling; the relative abundance was 1.1%, 22.4%, and 72.4%. Cochromatography of 32P-postlabeled 3'-hydroxy-1,N6-benzetheno-2'-deoxyadenosine 3',5'-bisphosphate with the 32P-postlabeled DNA-p-BQ reaction mixture established this compound, adduct 3, as the second most abundant product of the reaction.