Detection of Transient Intermediates in the Metal-Dependent Nonoxidative Decarboxylation Catalyzed by α-Amino-β-Carboxymuconate-ε-Semialdehyde Decarboxylase
作者:Tingfeng Li、John K. Ma、Jonathan P. Hosler、Victor L. Davidson、Aimin Liu
DOI:10.1021/ja073648l
日期:2007.8.1
Liu, A. J. Am. Chem. Soc. 2005, 127, 12282−12290 and Liu, A.; Zhang, H. Biochemistry 2006, 45, 10407−10411). Here, we report a rapid kinetic study of the ACMSD reaction using the cobalt(II)-reconstituted enzyme. Two previously undetected intermediates of the reaction are characterized. These are proposed to be the aminomuconate-e-semialdehyde (AMS) product of the decarboxylation in complex with the
金属酶介导的非氧化脱羧反应的第一个描述是由 α-氨基-β-羧基粘康酸-e-半醛脱羧酶 (ACMSD) (Li, T.; Walker, AL; Iwaki, H.; Hasegawa, Y.; Liu, AJ Am. Chem. Soc. 2005, 127, 12282−12290 和 Liu, A.;Zhang, H. Biochemistry 2006, 45, 10407−10411)。在这里,我们报告了使用钴 (II) 重组酶对 ACMSD 反应进行的快速动力学研究。表征了两个以前未检测到的反应中间体。这些被认为是脱羧的氨基粘康酸-e-半醛 (AMS) 产物,与酶和从 ACMSD 释放后的游离 AMS 复合。可以确定酶-底物复合物(2.4 × 106 s-1 M-1)的形成速率,AMS 产物的释放(8.8 s-1),AMS 自发环化为吡啶甲酸 (0.05 s-1),这是反应的最终