title: Formation of O6,7-dimethylguanine residues in calf thymus deoxyribonucleic acid treated with carcinogenic N-methyl-N-nitrosourea in vitro.
abstract: Treatment of calf thymus deoxyribonucleic acid (DNA) in vitro with a methylating carcinogen, N-methyl-N-nitrosourea (MNU), in phosphate buffer (pH 7.2) resulted in formation of O6,7-dimethylguanine residues in DNA besides the well-known methylated DNA adducts, 7-methylguanine, O6-methylguanine and 3-methyladenine. The product ratio (%) of O6,7-dimethylguanine versus 7-methylguanine was 0.32 after one MNU treatment. The significance of formation of O6,7-dimethylguanine residues in DNA is discussed briefly in relation to the carcinogenicity of MNU.
authors.affiliation: Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Kohda
authors.forename: N
authors.initials: N
authors.lastname: Sawada
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry / Q000187:drug effects*; D006147:Guanine / Q000031:analogs & derivatives* / Q000737:chemistry; D008770:Methylnitrosourea / Q000494:pharmacology*; D013950:Thymus Gland / Q000737:chemistry
chemical_list: C069874:O(6),7-dimethylguanine; D006147:Guanine; D008770:Methylnitrosourea; D004247:DNA