Methylhydrazine oxidation promoted by horseradish peroxidase-H2O2 or ferricyanide led to the generation of high yields of methyl radicals and to the formation of 7-methylguanine and 8-methylguanine upon interaction with calf thymus DNA. Methyl radicals were identified by spin-trapping experiments with α-(4-pyridyl-1-oxide)-N-tert-butyl nitrone and tert-nitrosobutane. The methylated guanine products were identified in the neutral hydrolysates of treated DNA by high pressure liquid chromatography (HPLC) analysis and spiking with authentic samples. The structure of 8-methylguanine, a product not previously reported in enzymatic systems, was confirmed by HPLC, UV absorbance, and mass spectrometry. The formation of 8-methylguanine suggests a possible role for carbon-centered radicals as DNA-alkylating agents.
|Original language||English (US)|
|Number of pages||4|
|Journal||Journal of Biological Chemistry|
|State||Published - 1990|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology