title: The in vitro and in vivo reaction at the N7-position of guanine of the ultimate carcinogen derived from benzolalpyrene.
abstract: The previously reported reaction at N2- and N7- of guanine following addition of 7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-BPDE) to an aqueous solution of DNA has been studied in more detail. The extent of reaction and the relative yields of N2- and N7-products was measured over the range of pH 4--7. The depurination following reaction at the N7-position of guanine was found to have a half-life of 3 h. Reaction of the isomeric 7 alpha,8 beta-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]-pyrene (syn-BPDE) with DNA gave the expected N2- and no N7-guanine product. When either benzo[a]pyrene or anti-BPDE was added to mouse embryo or Chinese hamster V79 cells respectively, a major N2-guanine product and a very minor adenine product were isolated from the DNA, but no N7-guanine product was detected.
mesh_terms: D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D006147:Guanine / Q000378:metabolism*; D066298:In Vitro Techniques; D051379:Mice
chemical_list: D001580:Benzopyrenes; D006147:Guanine; D004247:DNA