Inhibitory kinetics of mercuric ion on the activity of beta-N-acetyl-D-glucosaminidase from green crab (Scylla serrata).
Inhibitory kinetics of mercuric ion on the activity of beta-N-acetyl-D-glucosaminidase from green crab (Scylla serrata).
复制标题
DOI：
10.1016/j.ijbiomac.2005.10.006
复制
发表时间：
2006-11
影响因子：
8.2
通讯作者：
Jin-Jin Xie-Jin;Qing-Xi Chen;Ji-ping Zhang;Qin Wang;Xue Yang
中科院分区：
文献类型：
--
作者：
Jin-Jin Xie-Jin;Qing-Xi Chen;Ji-ping Zhang;Qin Wang;Xue Yang
研究了对氯汞苯甲酸盐（PCMB）对锯缘绿色β-N-乙酰-D-氨基葡萄糖苷酶（NAGase，EC 3.2.1.52）的化学修饰作用。结果表明，巯基对酶的活性是必不可少的。用酶抑制剂作用过程中底物反应动力学方法研究了氯化汞（HgCl_2）对酶的抑制动力学。动力学结果表明，低于1.0μM的汞离子（Hg ~（2+））对酶的抑制是一个可逆反应，具有残余活性，属于竞争性抑制。建立了Hg ~（2+）对该酶的抑制动力学模型，测定了微观速率常数，所得数据与模型拟合良好。实验结果还表明，只有一个分子的HgCl 2与酶分子结合，导致酶失去活性。上述结果表明，半胱氨酸残基是必不可少的活性，并位于酶的活性位点。
Chemical modification of p-chloromercuribenzoate (PCMB) on β-N-acetyl-d-glucosaminidase (NAGase, EC 3.2.1.52) from green crab (Scylla serrata) has been studied. The results show that sulfhydryl group is essential for the activity of the enzyme. Inhibitory kinetics of the enzyme by mercuric chloride (HgCl2) has been studied using the kinetic method of the substrate reaction during inhibitor of enzyme. The kinetic results show that the inhibition of the enzyme by mercuric ion (Hg2+) at lower than 1.0μM is a reversible reaction with residual activity and the inhibition belongs to be competitive. The inhibition kinetics model of Hg2+on the enzyme was set up and the microscopic rate constants were determined and the data obtained were well fitted with the model. It was also turned out that only one molecule of HgCl2binds to the enzyme molecule to lead the enzyme lose its activity. The above results suggest that the cysteine residue is essential for activity and is situated at the active site of the enzyme.