title: Cellular reactions of O6-methylguanine, a product of some alkylating carcinogens.
abstract: Cultures of a purine-requiring mutant of Chinese hamster ovary cells (CHO-104b), randomly bred hamster embryo cells, or Escherichia coli B(s-1) were treated with non-toxic doses of (3)H-labelled O(6)-methylguanine. DNA and RNA were isolated and subjected to enzymic digestion to nucleosides at pH8. The products of digestion were analysed by ion-exchange chromatography on columns of Dowex 50 (NH(4) (+) form) at pH8.9. No (3)H-labelled O(6)-methylguanosine was detected in nucleic acid digests. (3)H-labelled O(6)-methylguanine was O-demethylated yielding [(3)H]guanine in CHO-104b cells. Radioactivity in nucleic acid digests was associated with thymidine, guanosine, deoxyguanosine and an unidentified early-eluting product. Reports of similar unidentified products from nucleic acids labelled with various agents are discussed.
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000378:metabolism*; D002478:Cells, Cultured / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D006224:Cricetinae; D004247:DNA / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D006147:Guanine / Q000378:metabolism* / Q000633:toxicity / Q000031:analogs & derivatives; D006151:Guanosine / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008738:Methyl Ethers / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
chemical_list: D002273:Carcinogens; D008738:Methyl Ethers; D014316:Tritium; D006151:Guanosine; D006147:Guanine; D012313:RNA; D004247:DNA; C008449:O-(6)-methylguanine; D013936:Thymidine