在硫酸盐氧化酶内部进行域间电子转移的电压测量研究
Sean J Elliott1, Anne E McElhaney, Changjian Feng
1Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR England, UK.
Journal of the American Chemical Society
|September 26, 2002
概括
肝硫酸盐氧化酶 (SO) 电子转移受其heme b域和活性位所支配. 电极结合的SO表现出较慢的催化,这表明对高效的电子转移的形状变化有限.
科学领域:
- 生物化学 生物化学
- 电化学 电化学 电化学
- 酶动力学 酶动力学
背景情况:
- 硫酸盐氧化酶 (SO) 是硫代谢中的一个关键酶,利用heme b和辅因子.
- 了解SO的电子转移机制对于代谢途径分析至关重要.
研究的目的:
- 为了研究肝硫酸盐氧化酶 (SO) 固定在电极表面的电化学行为.
- 阐明B域和活性位在SO的催化电子传输中的作用.
主要方法:
- 使用 pyrolytic 石墨和黄金电极采用蛋白膜电压测量.
- 在存在或缺少硫酸盐的情况下分析了SO的电化学信号.
主要成果:
- 在+90 mV (vs SHE) 时,观察到一个明显的血红b域电化学信号.
- 硫酸盐结合诱导了催化波,表明由heme b域控制电子转移.
- 与溶液 (100s-1) 相比,观察到较低的周转率 (2-4s-1),这表明电极结合的SO的结构变化有限.
结论:
- 在SO中催化电子运输是由heme b域的电化学和分子内电子转移到位所决定的.
- 电极固定限制了SO的形状灵活性,影响了催化效率.
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