Evidence for environmentally coupled hydrogen tunneling during dihydrofolate reductase catalysis.
Evidence for environmentally coupled hydrogen tunneling during dihydrofolate reductase catalysis.
复制标题
二氢叶酸还原酶催化过程中环境耦合氢隧道效应的证据。
DOI：
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发表时间：
2003
影响因子：
15
通讯作者：
R. Allemann
中科院分区：
文献类型：
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作者：
G. Maglia;R. Allemann
通过停流光谱法研究了海栖热袍菌二氢叶酸还原酶催化过程中的氢化物转移。 NADPH 对二氢叶酸的还原表现出氘动力学同位素效应的双相温度依赖性。当温度高于 25 摄氏度时，KIE 与温度无关，而反应速率则强烈依赖于温度。低于 25 摄氏度时，KIE 变得依赖于温度，并且指前因子的比率成反比，这表明调节隧道距离的主动动力学发挥着更大的作用。
Hydride transfer during catalysis by dihydrofolate reductase from Thermotoga maritima has been studied by stopped flow spectroscopy. The reduction of dihydrofolate by NADPH showed a biphasic temperature dependence of the deuterium kinetic isotope effect. At temperatures above 25 degrees C the KIE was temperature independent, while the reaction rates were strongly temperature dependent. Below 25 degrees C the KIE becomes dependent on temperature, and the ratio of the preexponential factors is inverse, suggesting a greater role for active dynamics that modulate the tunneling distance.