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Title: Selective covalent binding of the active sulfate ester of the carcinogen 5-(hydroxymethyl)chrysene to the adenine residue of calf thymus DNA

Journal Article · · Chem. Res. Toxicol.; (United States)
DOI:https://doi.org/10.1021/tx00007a003· OSTI ID:6202160

5-(Hydroxymethyl)chrysene (5-HCR) sulfate, an active metabolite of the carcinogen 5-HCR, bound significantly in a covalent manner to the purine bases of calf thymus DNA through its 5-methylene carbon with loss of a sulfate anion when incubated at pH 7.4 and 37/degrees/C. From the DNA were isolated two purine base adducts by high-pressure liquid chromatography, and they were identified as N/sup 6/-((chrysen-5-yl)methyl)adenine and N/sup 2/((chrysen-5-yl)methyl)guanine with the corresponding synthetic specimens. The purine base adducts, appearing in the ratio 1 to 27 for guanine to adenine in the chromatogram, accounted for about 60% of the total covalent binding of 5-HCR sulfate to the DNA. 5-HCR sulfate also reacted specifically with the exocyclic amino groups of the purine bases of 2'-deoxyadenosine 5'-phosphate and 2'-deoxyguanosine 5'-phosphate at much lower rates than did with those of calf thymus DNA. Denaturing the DNA by heating followed by rapid cooling, covalent binding of 5-HCR sulfate to it markedly decreased with the increasing ratio of N/sup 2/-guanine to N/sup 6/-adenine adducts (1:3:6). These results strongly suggest that secondary structure of DNA has an influence on the covalent binding of 5-HCR sulfate and that intercalation of the sulfate ester into DNA base pairs plays an important role in its preferential binding to N/sup 6/ of the adenine residue of native DNA.

Research Organization:
Tokyo College of Pharmacy (Japan)
OSTI ID:
6202160
Journal Information:
Chem. Res. Toxicol.; (United States), Vol. 2:1
Country of Publication:
United States
Language:
English