Nontargeted Analysis of DNA Adducts by Mass-Tag MS: Reaction of p-Benzoquinone with DNA

作者：Wang Poguang; Gao Jianxin; Li Guodong; Shimelis Olga; Giese Roger W^*

来源：Chemical Research in Toxicology, 2012, 25(12): 2737-2743.

DOI：10.1021/tx300363a

Using a method in which DNA adducts are discovered based on their conversion in a nucleotide form to phosphorimidazolides with isotopologue benzoylhistamines (or p-bromobenzoylhistamine) prior to detection by MALDI-TOF-MS, we have profiled the adducts that form when calf thymus DNA is reacted in vitro with p-benzoquinone (BQ). We find, as relative values normalized to 100% of adducts observed, 79% BQ-dCMP, 21% BQ-methyl-dCMP (a new DNA adduct), and trace amounts of BQ-dAMP and BQ-dGMP. Because mC is 5% of C in this DNA, the reaction of BQ with DNA in vitro is about five times faster at methyl-C than C. When equal amounts of dCMP and methyl-dCMP are reacted with BQ, equal amounts of the corresponding adducts are observed. Thus, the microenvironment of methyl-C in DNA enhances its reactivity relative to C with BQ. In a prior, similar study, but based on analysis by P-32-postlabeling, the second most abundant adduct was assigned to BQ-A, apparently because of comigration of the BQ-A and BQ-methyl-C adducts (as bisphosphates) in the chromatographic step. Because the calf thymus DNA (used as received) was contaminated with RNA, we also detected the ribonucleotide adduct, BQ-CMP.

• 出版日期2012-12
• 单位东北大学