Acid lability of the hydrocarbon-deoxyribonucleoside linkages in 7,12-dimethylbenz[a]anthracene-modified deoxyribonucleic acid.

DNA containing bound radioactive 7,12-dimethylbenz[a]anthracene was isolated from mouse fetal cell cultures exposed to this carcinogen. The carcinogen-deoxyriboside adducts within the DNA were found to be sensitive to acid-catalyzed hydrolysis. Adducts derived from reaction of a syn-dihydrodiol epoxide with deoxyadenosine residues in DNA were the most sensitive to acid and were hydrolyzed to yield a 1,2,3,4-tetrahydrotetraol of 7,12-dimethylbenz[a]anthracene under mild conditions. The structure of this tetraol was established by synthesis and mass spectrometry. Although definitive structures cannot be assigned at present to the nucleic acid adducts of this potent carcinogen, the present findings confirm and extend earlier work assigning partial structures to the major adducts.