Identification of the major adducts formed by reaction of benzo(a)pyrene diol epoxide with DNA in vitro.

Abstract
Covalent binding of the benzo[a]pyrene metabolite (.+-.)7.beta.,8.alpha.-dihydroxy-9.alpha.,10.alpha.-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene to calf thymus DNA was investigated. Enzymatic hydrolysis of the carcinogen-modified DNA and subsequent separation via reversed phase high pressure liquid chromatography resulted in the detection and isolation of 7 distinct products. High resolution mass spectrometry indicates that these products are covalent adducts of deoxyguanosine, deoxyadenosine and deoxycytidine. The deoxyguanosine and deoxyadenosine adducts involve binding between the activated hydrocarbon (benzo[a]pyrene diol epoxide) and exocyclic amino groups of the respective purines.