Covalent PAH o-Quinone-DNA Adducts

Two types of covalent PAH o-quinone-DNA adducts are possible. The first type involves the formation of stable covalent adducts that may result from either 1,4- or 1,6-Michael addition of the N2-exocyclic amino group of dGuo or the N exocyclic amino group of dAde. Evidence exists for these adducts in reactions of B [a] P-7,8-dione with either deoxyribonucleosides or bulk DNA [94, 95]. In the former case, 

The second type of PAH o-quinone covalent adduct involves formation of depurinating adducts that result from 1,4- or 1,6-Michael addition of the N7 ring nitrogen of guanine or adenine. Evidence for these adducts were observed in vitro by reaction of PAH o-quinones with deoxyribonudeosides under acidic conditions or by reaction of PAH o-quinones with calf thymus DNA [97]. These adducts were fully characterized by NMR and LC/MS. Recently, interest in the covalent PAH o-quinone adducts has diminished based on the accumulated evidence that PAH 

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