title: Identification of the major adducts formed by reaction of 5-methylchrysene anti-dihydrodiol-epoxides with DNA in vitro.
abstract: 5-Methylchrysene is metabolically converted to the bay-region dihydrodiol-epoxides, trans-1,2-dihydroxy-anti-3,4-epoxy-1,2,3,4-tetrahydro-5-methylchrysene (DE-I), in which the methyl group and the epoxide ring are in the same bay region, and trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydro-5-methylchrysene (DE-II). Previous studies have indicated that DE-I is more important in 5-methylchrysene carcinogenesis than is DE-II. Both DE-I and DE-II were individually reacted with calf thymus DNA in vitro. The DNA was enzymatically hydrolyzed to deoxyribonucleosides, and the modified deoxyribonucleosides were separated by chromatography on Sephadex LH-20 and analyzed by high-performance liquid chromatography. One major adduct and seven minor adducts were formed from each dihydrodiol-epoxide. The major adduct was, in each case, characterized by its pH-dependent partition coefficient, stability to base, mass spectrum, ultraviolet spectrum, and nuclear magnetic resonance spectrum as a deoxyguanosine derivative resulting from addition of the exocyclic amino group of deoxyguanosine to the benzylic carbon of the epoxide ring of the dihydrodiol-epoxide. The results of this study show that the major DNA adducts formed from 5-methylchrysene via DE-I and DE-II are structurally similar.
mesh_terms: D000818:Animals; D002273:Carcinogens; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002911:Chrysenes; D004247:DNA; D009682:Magnetic Resonance Spectroscopy; D010616:Phenanthrenes; D013329:Structure-Activity Relationship; D013950:Thymus Gland
chemical_list: D002273:Carcinogens; D002911:Chrysenes; D010616:Phenanthrenes; C041436:9,10-epoxy-7,8-dihydroxy-7,8,9,10-tetrahydro-5-methylchrysene; C037783:1,2-dihydroxy-epoxy-1,2,3,4-tetrahydro-5-methylchrysene; D004247:DNA