Study of the methylation and lack of deamination of deoxyribonucleic acid by N-methyl-N'-nitro-N-nitrosoguanidine.
1. DNA labelled with (14)C in the purine residues was prepared by treating newborn rats with [(14)C]formate and killing them for preparation of nucleic acids at 11-17 months. This DNA was incubated with N-methyl-N'-nitro-N-nitrosoguanidine, and then analysed for products of methylation and deamination reactions. 2. Evidence was found for the formation of 7-methylguanine and a smaller amount of 3-methyladenine, and, after preliminary denaturation of the DNA, 1-methyladenine was detected. The presence of cysteine increased the extent of methylation. No evidence was found for the formation of xanthine or hypoxanthine, even at pH5.5.
D000225:Adenine / Q000138:chemical synthesis; D000818:Animals; D000831:Animals, Newborn; D002247:Carbon Isotopes; D055598:Chemical Phenomena; D002621:Chemistry; D003545:Cysteine; D004247:DNA / Q000096:biosynthesis; D005260:Female; D006146:Guanidines; D006147:Guanine / Q000138:chemical synthesis; D007042:Hypoxanthines; D008745:Methylation; D009603:Nitroso Compounds; D051381:Rats; D014970:Xanthines
D002247:Carbon Isotopes; D006146:Guanidines; D007042:Hypoxanthines; D009603:Nitroso Compounds; D014970:Xanthines; D006147:Guanine; D004247:DNA; D000225:Adenine; D003545:Cysteine