两种SOD模拟物对氧自由基所致质粒pBR322DNA损伤的防护作用

Inhibitory effect of two mimics of superoxide dismutase on damage to pBR322 DNA induced hy oxygen radicals

以自由基所致质粒ｐＢＲ３２２ＤＮＡ在琼脂糖电泳中的构象改变为实验模型，结合ＥＳＲ技术观察了南京大学配位化学研究所首次合成的二十员大环双核铜和线形二氧四胺铜两种ＳＯＤ模拟物对Ｏ＿２和·ＯＨ所致ＤＮＡ损伤的防护作用及清除氧自由基效能的差异。结果表明，两种ＳＯＤ模拟物对Ｏ＿２的清除效能显著，并对其所致ＤＮＡ损伤具有明显的抑制作用，而对·ＯＨ所致损伤未见明显的防护效能．

Plasmid pBR322 DNA was exposed to superoxide(O_2 ) and hydroxyl radicals(· OH) generated fromxanthine / xanthine oxidase and H_2O_2 / Fe￣2+system, respectively. The conformational modifications were ana-lyzed by agarose electrophoresis. Twenty- membered macrocyclic bicoper(II) and 13- membered macrocvclicdioxotetramine copper(II), two mimics of superoxide dismutase(SOD) newly synthesized by the Nanjing Universi-ty,inhibited the damage to pBR322 mediated by O_2, but had no effect on that mediated by· OH。 ESRmeasurement further indicated that both mimics could scavenge O_2, but not· OH。