Metabolic activation of benz[a]anthracene in hamster embryo cells: the structure of a guanosine-anti-BA-8,9-diol 10,11-oxide adduct.

The structures of two guanosine-hydrocarbon adducts prepared from polyG that had been incubated with anti-BA-8,9-diol 10,11-oxide (r-8,t-9-dihydroxy-t-10,11-oxy-8,9,10,11-tetrahydrobenz[a]anthracene) were investigated by examining their H-n.m.r. spectra, their pK values before and after treatment with nitrous acid and their stabilities in 1M KOH. The data show that both of the adducts were formed by reaction between the exocyclic amino group of guanine and the 11-position of the diolepoxide. One of these adducts is indistinguishable from an adduct isolated from hamster embryo cells that had been treated with benz[a]anthracene and that may contribute to the biological activity of this weak carcinogen.