在单氨酸氧化酶a中由电子偏磁共振对共价结合的阳离子黄素基的表征
Christopher W M Kay1, Hassane El Mkami, Gianluca Molla
1Department of Biology, University College London, UK. c.kay@ucl.ac.uk
Journal of the American Chemical Society
|November 30, 2007
概括
单氨基氧化酶 (MAO) A和B酶含有阳离子黄基,而不是铁基. 毛泽东是一个人.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 频谱学是一种光谱学.
背景情况:
- 关于部分减少的单胺氧化酶 (MAO) A.A.中存在的基因物种存在矛盾的报告.
- 之前的研究表明,MAO A 含有离子黄和铁基,而 MAO B 仅显示出离子黄基.
- 根据MAO A的发现,提出了对MAO的修订后的激进机制.
研究的目的:
- 解决在MAO A.中报告的基因物种的差异.
- 通过使用高频电子磁共振 (EPR) 来研究MAO A的基态形式.
- 为了比较MAO A与d-氨基酸氧化酶 (DAAO) 的基因物种和电子结构.
主要方法:
- 在94 GHz (W频段) 的连续波电子磁共振 (EPR) 被用来研究MAO A.
- 脉冲电子核双共振 (ENDOR) 频谱在9 GHz (X频段) 记录了MAO A和DAAO.
- 进行密度函数理论 (DFT) 计算来分析超细合模式.
主要成果:
- 发现MAO A和DAAO都只含有阳离子黄素基.
- 在MAO A和DAAO黄素之间观察到明显的高精度合模式,由C8alpha位置的差异解释.
- MAO A有一个黄素在C8alpha与氨酸共价结合,而DAAO有一个非共价结合的黄素.
结论:
- 这项研究没有证实MAO A中存在铁基.
- 在C8alpha的flavin结合的差异影响观察到的EPR光谱.
- 对于MAO催化,建议使用类似于DAAO的直接化物转移机制.
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