KINETICS OF THE LACTATE-DEHYDROGENASE REACTION IN HIGH-VISCOSITY MEDIA
KINETICS OF THE LACTATE-DEHYDROGENASE REACTION IN HIGH-VISCOSITY MEDIA
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DOI：
10.1016/0167-4838(89)90273-2
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发表时间：
1989-10-05
期刊：
影响因子：
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通讯作者：
SABUROVA, EA
中科院分区：
文献类型：
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作者：
DEMCHENKO, AP;RUSYN, OI;SABUROVA, EA
研究了培养基粘度对乳酸脱氢酶反应动力学参数的影响。粘度的增加导致丙酮酸还原反应和乳酸氧化反应的催化速率急剧下降。结果表明，随着黏度的增加，催化步骤及其相关的构象运动是唯一显著减缓的步骤。反应对介质介电性质的变化不敏感。在速率常数和粘度之间观察到的反幂函数不能用绝对反应速率理论来解释。然而，它可以很容易地解释在克拉默斯理论的基础上，处理跃迁的激活势垒作为一个扩散运动在随机力的领域。介质粘度对动力学参数的影响表明溶剂的动力学与蛋白质分子的构象运动之间存在强耦合，这与催化步骤有关。
The effect of the medium viscosity on kinetics parameters of lactate dehydrogenase reaction was studied. The viscosity increase results in a sharp decline in the catalytic rate for both the pyruvate reduction and lactate oxidation reactions. It is shown that the catalytic step and its associated conformational motions is the only step which is considerably retarded when the visocity increases. The reaction is not sensitive to changes in the dielectric properties of the medium. An inverse power function observed between the rate constant and viscosity cannot be explained by the theory of absolute reaction rates. However, it can easily be interpreted on the basis of the Kramers theory dealing with the transition over the activation barrier as a diffusional motion in the field of random forces. The influences of the medium''s viscosity on the kinetic parameters indicates the existence of strong coupling between the dynamics of the solvent and the conformational motions of the protein molecule, which are correlated with the catalytic step.