对于酶催化化的一种同位素效应
Christopher M Reddy1, Li Xu, Nicholas J Drenzek
1Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA. creddy@whoi.edu
Journal of the American Chemical Society
|December 6, 2002
概括
酶类化显示出显著的动态同位素效应,区分天然的化有机化合物 (COC) 与基于同位素比的人造化合物.
科学领域:
- 环境化学环境化学
- 生物化学 生物化学
- 同位素地球化学 同位素地球化学
背景情况:
- 化有机化合物 (COC) 在各种环境和生物样本中普遍存在.
- 它们的起源可以是自然的或人为的,这对来源归因构成了挑战.
- 同位素比是区分这些来源的潜在标记.
研究的目的:
- 为了研究酶催化化中的同位素效应.
- 确定这种效应是否能区分自然和人为的COC.
- 为了评估动态同位素效应 (KIE) 的酶与非酶化.
主要方法:
- 使用Caldariomyces fumago的氧化酶对芳香基质 (1,3,5-三甲基和3,5-二甲基) 的酶化.
- 测量同位素比率 (k35/k37) 以计算动态同位素效应 (KIE).
- 与使用低酸盐的非酶化化进行比较.
主要成果:
- 在酶催化化中观察到大量的动态同位素效应 (KIE).
- 1,3,5-三甲基的KIE值为1.012和3,5-二甲基的1.011.
- 非酶性化产生了显著较小的KIE,突出了酶的作用.
结论:
- 酶催化化表现出显著的动态同位素效应.
- 这种酶途径可以产生具有明显同位素特征的天然COC.
- 同位素比为区分天然和人为的COC提供了一个有前途的方法.
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