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A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
Published on: October 2, 2012
马隆酸半化物脱碳酶的水解酶活性:机械学和进化方面的影响
Gerrit J Poelarends1, Hector Serrano, William H Johnson
1Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, The University of Texas, Austin, Texas 78712, USA.
Journal of the American Chemical Society
|December 2, 2004
概括
马洛半甲酸脱碳酶 (MSAD) 呈现出新型的酶活性,将特定基质转化为乙烯基酸. 这种杂乱的功能,以及它的脱碳酶作用,表明在 tautomerase 超级家族内存在不同的进化.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 蛋白质科学 蛋白质科学
背景情况:
- 马洛半甲酸脱碳酶 (MSAD) 属于 tautomerase 超级家族,其特点是β-α-β 折叠和一种催化 N 终端的 proline.
- 陶托马酶超级酶家族的酶具有结构同质性和保留的触媒机制,涉及.
研究的目的:
- 为了研究马隆酸半化物脱碳酶 (MSAD) 的酶活性.
- 阐明MSAD在 tautomerase超级家族中的催化机制和进化起源.
主要方法:
- 酶动力学测试以确定酸酶活性的kcat/Km值.
- 15N NMR 定位以确定催化式烯残留物 (Pro-1) 的 pKa.
主要成果:
- MSAD表现出散乱的酸酶活性,将2-oxo-3-pentynoate转化为乙烯基酸盐,其kcat/Km为6.0 x 10^2 M^-1 s^-1.
- Pro-1和Arg-75对于脱碳酶和酶活动都至关重要.
- 确定Pro-1的pKa为~9.2,这表明它通过结或静电相互作用在基质极化中的作用.
- 与trans-3-chloroacrylic acid dehalogenase (CaaD) 的共享酸酶活性和Pro-1 pKa表明了不同的进化.
结论:
- MSAD既具有脱碳酶活性,也具有散乱的酸酶活性,由Pro-1和Arg-75.5介导.
- 催化机制可能涉及Pro-1对基板碳基氧的偏振.
- MSAD和CaaD很可能是从一个共同的祖先进化而来的,保留了祖先对水合物添加的催化能力.
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