Abstract
The carcinogen, benzo[a]pyrene, was covalently attached to poly(G) by liver microsomes from rats pretreated with 3-methylcholanthrene. The complex was hydrolyzed with enzymes or base and products were isolated by Sephadex chromatography. Absorbance and flurorescence spectra of the products fit that of a red-shifted pyrene aromatic system and suggest that metabolism occurred at the 7-, 8-, 9- and 10-positions of the hydrocarbon. Benzanthracene or chrysene fluorescence were not observed in these preparations. Benzo[a]pyrene derivatives were synthesized and purified by high pressure liquid chromatography. Dehydration of 7,8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene resulted in the formation of small amounts of 7-oxo-7,8,9,10-tetrahydrobenzo[a]pyrene. A 7-keto species was also observed after similar treatment of the hydrocarbon-poly(G) hydrolysis products. Evidence of dehydration at the 9,10-positions was not observed. The hydrocarbon covalently bound to poly(G) is a derivative of 7,8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene with nucleic acid substitution at C-10 or 9.

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