Reaction of DNA Peroxyl Radicals with Cysteamine and Glutathione: The Formation of Sulfoxyl Radicals
The oxygen enhancement effect has been attributed to defect (radical) fixation by oxygen which prevents repair by sulfhydryls (1–4). Actually, in model systems, oxygen in the absence of thiols is a slight radioprotector of DNA and does not act to increase damage (5,6). Indigenous thiols not only account for the radioprotective effects but their radical reactions in the presence of oxygen are also a likely source of the oxygen enhancement effect. Prutz has suggested in recent studies that disulfide anion radicals formed by thiyl radical attack on thiol (reaction 1) are the primary species responsible for the radioprotective effect of thiols (7).
KeywordsPeroxyl Radical Hydrogen Abstraction Radioprotective Effect Thiyl Radical Reactive Hydrogen Abstraction
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