银离子对精氨酸激酶的影响：抑制动力学

The effect of Ag+ on arginine kinase: inhibition kinetics.

作者信息

Sheng Q, Lu Z-R, Mu H, Zou H-C, Zou F, Yao S-J

机构信息

Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou, P. R. China.

出版信息

J Biomol Struct Dyn. 2009 Aug;27(1):59-64. doi: 10.1080/07391102.2009.10507296.

DOI:10.1080/07391102.2009.10507296

PMID:19492863

Abstract

We studied the effects of Ag(+) on arginine kinase (AK) from Fenneropenaeus chinensis. Ag(+) inactivated the activity of AK in a dose dependent manner (IC(50) = 15 microM). Kinetic studies showed that the inactivation of AK by Ag(+) was reversible and occurred in a noncompetitive inhibition manner (K(i) = 2.8 microM). Spectroflurorimetry results showed that Ag(+) did not induce conspicuous tertiary structural changes in AK at the corresponding concentration ranges of inactivation studies. However, the secondary structure measured by circular dichroism was slightly changed by Ag(+). Taken together, these data suggest that the active site of AK is flexible, with the complete loss of activity occurring prior to significant changes in overall structures. Our study provides important insight into the inhibitory mechanism of Ag(+) on AK and increases our understanding of the influence of Ag+ on the mechanism of this metabolic enzyme.

摘要

我们研究了银离子（Ag(+)）对中国明对虾精氨酸激酶（AK）的影响。Ag(+)以剂量依赖性方式使AK的活性失活（半数抑制浓度（IC(50)）= 15微摩尔）。动力学研究表明，Ag(+)对AK的失活是可逆的，并且以非竞争性抑制方式发生（抑制常数（K(i)）= 2.8微摩尔）。荧光光谱法结果表明，在失活研究的相应浓度范围内，Ag(+)未诱导AK发生明显的三级结构变化。然而，通过圆二色性测量的二级结构受到Ag(+)的轻微影响。综上所述，这些数据表明AK的活性位点具有灵活性，在整体结构发生显著变化之前活性就已完全丧失。我们的研究为Ag(+)对AK的抑制机制提供了重要见解，并增进了我们对Ag+对这种代谢酶机制影响的理解。