Adam W, Grimm G N, Saha-Möller C R
Institute of Organic Chemistry, University of Würzburg, Germany.
Free Radic Biol Med. 1998 Jan 15;24(2):234-8. doi: 10.1016/s0891-5849(97)00218-9.
The photolysis of N-isopropoxypyridine-2-thione (1b) and of N-tert-butoxypyridine-2-thione (1c) generated alkoxyl radicals as confirmed by trapping experiments with DMPO and subsequent EPR spectroscopy. Upon UVA irradiation, the alkoxyl-radical sources induce strand breaks in supercoiled pBR 322 DNA, which was analyzed by gel electrophoresis. The participation of type I (electron transfer, H abstraction) or type II (1O2) photosensitization in the DNA cleavage by the oxyl-radical sources 1a-d or their photoproducts could be excluded. The present study establishes unequivocally that alkoxyl and benzoyloxyl, as well as hydroxyl radicals, cause strand breaks in DNA and, thus, may play a significant role in the DNA cleavage by peroxides.
通过用DMPO进行捕获实验及随后的电子顺磁共振光谱证实，N-异丙氧基吡啶-2-硫酮（1b）和N-叔丁氧基吡啶-2-硫酮（1c）的光解产生了烷氧基自由基。在UVA照射下，烷氧基自由基源会导致超螺旋pBR 322 DNA发生链断裂，通过凝胶电泳对此进行分析。可以排除I型（电子转移、氢原子提取）或II型（单线态氧）光敏化在由氧基自由基源1a - d或其光产物导致的DNA裂解中的作用。本研究明确证实，烷氧基、苯甲酰氧基以及羟基自由基会导致DNA链断裂，因此可能在过氧化物引起的DNA裂解中起重要作用。
