芬顿体系中嘧啶核苷酸自由基的自旋捕获
The spin trapping of pyrimidine nucleotide free radicals in a Fenton system.
作者信息
Flitter W D, Mason R P
机构信息
Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709.
出版信息
Biochem J. 1989 Aug 1;261(3):831-9. doi: 10.1042/bj2610831.
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.
利用自旋捕集电子顺磁共振技术，研究了由芬顿体系产生的羟基自由基与嘧啶脱氧核糖核苷酸的反应。采用自旋捕集剂叔丁基亚硝基苯来捕获羟基自由基与这些核苷酸反应形成的二级自由基。此处给出的结果表明，羟基自由基对胸腺嘧啶、2-脱氧胞苷5-单磷酸酯和2-脱氧尿苷5-单磷酸酯的攻击产生了核苷酸衍生的自由基。结果表明，·OH自由基攻击主要发生在嘧啶碱基的碳-碳双键处。电子顺磁共振研究表明，与先前使用X射线或γ射线辐照产生羟基自由基的作者所获得的结果具有良好的相关性。还使用硫代巴比妥酸测定法来监测芬顿体系对核苷酸造成的损伤。这些结果与自旋捕集研究在定性上一致。
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