The spin trapping of pyrimidine nucleotide free radicals in a Fenton system.
The reaction of the hydroxyl radical, generated by a Fenton system, with pyrimidine deoxyribonucleotides was investigated by using the e.s.r. technique of spin trapping. The spin trap t-nitrosobutane was employed to trap secondary radicals formed by the reaction of the hydroxyl radical with these nucleotides. The results presented here show that hydroxyl-radical attack on thymidine, 2-deoxycytidine 5-monophosphate and 2-deoxyuridine 5-monophosphate produced nucleotide-derived free radicals. The results indicate that .OH radical attack occurs predominantly at the carbon-carbon double bond of the pyrimidine base. The e.s.r. studies showed a good correlation with previous results obtained by authors who used x- or gamma-ray irradiation to generate the hydroxyl radical. A thiobarbituric acid assay was also used to monitor the damage produced to the nucleotides by the Fenton system. These results showed qualitative agreement with the spin-trapping studies.
Flitter
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Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
Mason
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D003843:Deoxycytidine Monophosphate / Q000378:metabolism; D003856:Deoxyuracil Nucleotides / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D006878:Hydroxides / Q000378:metabolism*; D017665:Hydroxyl Radical; D011742:Pyrimidine Nucleotides / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism
D003856:Deoxyuracil Nucleotides; D005609:Free Radicals; D006878:Hydroxides; D011742:Pyrimidine Nucleotides; D003843:Deoxycytidine Monophosphate; D017665:Hydroxyl Radical; C007267:2'-deoxyuridylic acid; D013936:Thymidine