32P-postlabeling analysis of adducts formed from 1-phenylazo-2-hydroxynaphthalene (Sudan I, Solvent Yellow 14) with DNA and homopolydeoxyribonucleotides.

A 32P-postlabeling assay was employed for detection and quantitation of DNA adducts formed with carcinogenic 1-phenylazo-2-hydroxynaphthalene (Sudan I, Solvent Yellow 14) activated by a peroxidase system. Enrichment of adducts by digestion with nuclease P1 or by extraction into n-butanol prior to 32P-labeling was used. Both enrichment procedures exhibited comparable results for recovery of individual DNA adduct spots. Co-chromatographic analyses of adduct spots obtained by reaction with DNA and homopolydeoxy-ribonucleotides showed that four out of the eight major Sudan I-DNA adducts were formed by reaction of activated Sudan I with deoxyadenosine or deoxyguanosine in DNA. The accuracy of quantitation of adducts by 32P-postlabeling procedure is discussed.