Metabolic activation of benz(a)anthracene: fluorescence spectral evidence indicates the involvement of a non-'bay-region' diol-epoxide.

The fluorescence spectral properties of the principal hydrocarbon-nucleoside adducts present in hydrolysates of DNA that had been isolated from hamster embryo cells or from mouse skin treated with benz(a)anthracene have been examined using photon-counting spectrophotofluorimetry and compared with the spectral properties of the products formed when different diol-epoxides derived from benz(a)anthracene react with nucleic acid in solution. The adducts were separated by chromatography on LH20 Sephadex columns and purified by high pressure liquid chromatography. The spectra obtained are phenanthrene-like and not anthracene-like, a result that is consistent with metabolic activation occurring, through the formation of a vicinal diol-epoxide, in the 8,9,10,11-ring, rather than in the 1,2,3,4-ring of this hydrocarbon.