Comparison of the cellular DNA-bound products of benzo(alpha)pyrene with the products formed by the reaction of benzo(alpha)pyrene-4,5-oxide with DNA.

DNA isolated from mouse embryo cell cultures that had been treated with [3H]benzo(alpha)pyrene was degraded with enzymes to deoxyribonucleosides, and the hydrocarbon-deoxyribonucleoside products were isolated by chromatography on a Sephadex LH20 column eluted with a water: methanol gradient. The hydrocarbon-deoxyribonucleoside products were not identical to those found in similar chromatograms of enzyme digests of DNA that had been reacted with benzo(alpha)pyrene-4,5-oxide in aqueous ethanol solution. This finding suggests that the metabolic activation of benzo(alpha)pyrene that results in this hydrocarbon becoming covalently bound to DNA in mouse embryo cells in culture may be more complex than simply formation of a K-region epoxide and reaction of that compound with the cellular DNA.