在催化过程中通过铜超氧化物脱酶的电子转移机制
Valeriy V Smirnov1, Justine P Roth
1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
Journal of the American Chemical Society
|December 21, 2006
概括
这项研究研究了铜超氧化物脱酶 (SOD) 催化中的活性氧中间体. 结果表明CuII-O2-I中间体和超氧化物减少的速率决定性质子转移机制.
科学领域:
- 生物化学 生化学
- 酶学 是一种酶学.
- 生物有机化学 生物有机化学
背景情况:
- 铜超氧化物脱酶 (SOD) 对于排毒活性氧物种至关重要.
- 了解SOD的催化机制和中间体对于理解氧化应激路径至关重要.
研究的目的:
- 在铜超氧化物脱酶 (SOD) 催化过程中研究活性氧中间体.
- 使用动态同位素效应阐明超氧化物氧化和SOD还原的机制.
主要方法:
- 采用同位素分离技术,使用自然丰富的试剂.
- 测量了对酶催化和静态反应的竞争性氧运动同位素效应 (KIEs).
- 在量子力学电子转移理论的框架内分析数据.
主要成果:
- 证据反对O2*-氧化外层机制,提出CuII-O2-I中间体.
- 观察到SOD催化O2*-氧化的反向 (<1) KIE,类似于合成铜化合物.
- 检测到一种对酶性O2*-减少的反向KIE,这表明决定速率的质子转移.
结论:
- 铜SOD的催化机制涉及一个CuII-O2-I中间体.
- 超氧化物被SOD氧化可能是通过内部球的电子转移机制进行的.
- 确定速率的质子转移与SOD的超氧化物的酶性降解有关.
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