Reaction between ortho-semiquinones and oxygen: pulse radiolysis, electron spin resonance, and oxygen uptake studies.
Reaction between ortho-semiquinones and oxygen: pulse radiolysis, electron spin resonance, and oxygen uptake studies.
复制标题
邻半醌和氧气之间的反应：脉冲放射分解、电子自旋共振和摄氧量研究。
DOI：
10.1016/0003-9861(88)90259-7
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发表时间：
1988
影响因子：
3.9
通讯作者：
Truscott,TG
中科院分区：
文献类型：
--
作者：
Kalyanaraman,B;Korytowski,W;Pilas,B;Sarna,T;Land,EJ;Truscott,TG
某些对苯二酚类抗肿瘤药物对肿瘤细胞的细胞毒性或心脏毒性副作用被归因于相应的半喹酮类化合物和衍生的超氧阴离子自由基。也有人认为，邻半喹酮，包括那些在黑素合成过程中产生的，通过邻苯二酚(胺)S的单电子氧化或相应的苯二酚的单电子还原产生，与分子氧反应生成超氧化物和过氧化氢。此外，研究还表明，邻苯二酚(胺)S形成不可环化的苯醌，对黑素细胞的细胞毒性比形成环化的苯醌的细胞毒性更大。为了进一步提供氧与邻半喹酮相互作用的动力学信息，我们用脉冲辐解法直接测定了各种邻半喹酮与分子氧的反应速率。辣根过氧化物酶/过氧化氢体系也产生了相应的邻苯二酚-(胺)S的半喹酮类化合物，并用自旋稳定化方法进行了电子自旋共振光谱检测。用标准的Clark氧电极监测氧耗。我们的数据表明，由于⩽105M−1S−1，邻苯二酚(胺)S和邻苯二酚雌激素与分子氧的反应速率不等于或大于等于，而羟基取代邻苯二酚(胺)S的半喹酮与氧气的反应速率为−=10~6-107M−1S−1。
The cytotoxicity to tumor cells or cardiotoxic side effects of certainpara-quinone antitumor drugs have been attributed to the corresponding semiquinones and derived superoxide and hydroxyl radicals. It has also been suggested thatortho-semiquinones, including those that arise during melanogenesis, produced via either the one-electron oxidation of catechol(amine)s or the one-electron reduction of the corresponding quinones, react with molecular oxygen to give Superoxide and hydrogen peroxide. Furthermore it has been shown that catechol(amine)s which form noncyclizable quinones are more cytotoxic toward melanogenic cells than those forming cyclizable quinones. In order to provide further kinetic information on the interaction of oxygen withortho-semiquinones, using pulse radiolysis we directly measured the rates of reaction of variousortho-semiquinones with molecular oxygen. The semiquinones of the corresponding catechol-(amine)s were also produced by the horseradish peroxidase/hydrogen peroxide system, and detected by electron spin resonance spectroscopy using the spin stabilization method. Oxygen consumption was monitored using a standard Clark oxygen electrode. Our data indicate that whileortho-semiquinones from catechol(amine)s and catechol estrogens do not react with molecular oxygen at a rate equal to or greater thank⩽ 105m−1s−1, semiquinones from hydroxy-substituted catechol(amine)s react with dioxygen with rates in the rangek= 106-107m−1s−1.