电子库存,动力赋值 (E(n)),结构和化酶周转中间体与C2H2和CO的结合
Hong-In Lee1, Morten Sørlie, Jason Christiansen
1Department of Chemistry Education, Kyungpook National University, Daegu, 702-701, Korea. leehi@knu.ac.kr
Journal of the American Chemical Society
|November 10, 2005
概括
酶S(EPR1) 中间体,可能含有与铁-辅因子结合的乙烯,被确定为产品复合物. 这项研究将酶中间体与动力学方案相关联,定义它们的电子状态.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 酶动力学 酶动力学
背景情况:
- 基酶酶对于生物固定至关重要.
- 了解酶降解基质的机制需要对反应中间体进行详细的描述.
- 铁- (FeMo) 辅因子是基质转化的活性位点.
研究的目的:
- 为了阐明基酶中S(EPR1) 中间体的结构和电子状态.
- 为了将酶中间体与已建立的动力学模型相关联,如洛威-索恩利方案.
- 在基质周转过程中定义FeMo辅因子的化学状态.
主要方法:
- 高场电子核双共振 (ENDOR) 光谱 (1H和57Fe).
- 连续波 (CW) 和Mims脉冲的ENDOR技术.
- 用57Fe. 的同位素丰富.
主要成果:
- 介质S(EPR1) 被确定为一种产品复合物,可能与乙烯 (C2H4) 作为铁环结合于FeMo辅因子.
- 在S(EPR1) 中的FeMo辅因子表现出类似于CO结合中间体的值,减少了2个电子 (m=2).
- 引入了一种新概念"电子库存",以将中间体与洛伊-索恩利还原状态相关联,将S(EPR1) 赋予E(n=4和lo-CO赋予E(n=2).
结论:
- 这项研究提供了Lowe-Thorneley动态状态和酶酶的定义化学状态之间的第一个相关性.
- 这些发现澄清了乙烯的结合方式和酶循环过程中FeMo辅因子的电子配置.
- "电子库存"为了解酶中间体中的电子分布提供了一个框架.
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