过氧化氢对锯缘青蟹N-乙酰-β-D-氨基葡萄糖苷酶的抑制动力学  

Inhibitory kinetics on NAGase of mud crab(Scylla serrata) by hydrogen peroxide

作　　者：谢进金[1] 林建成 张继平[1] 颜雅雯[1] 王勤[1] 陈清西[1] 

机构地区：[1]厦门大学生命科学学院细胞生物学与肿瘤细胞工程教育部重点实验室 [2]厦门市妇幼保健院,福建厦门361005

出　　处：《台湾海峡》2006年第4期459-464,共6页Journal of Oceanography In Taiwan Strait

基　　金：国家自然科学基金资助项目(40576066)

摘　　要：研究过氧化氢对锯缘青蟹N-乙酰-β-D-氨基葡萄糖苷酶活力的影响及抑制动力学.其结果表明,过氧化氢对该酶有显著的抑制作用,随着过氧化氢浓度的增高,酶活力呈指数下降,测出可使酶活力下降50%的过氧化氢浓度(抑制半衰期,IC50)为115mmol/dm3.低浓度过氧化氢对该酶的抑制过程显示为可逆效应.采用底物反应动力学方法研究过氧化氢对该酶的抑制作用动力学并建立动力学模型,测定游离酶(E)和酶-底物络合物(ES)的微观抑制速度常数k+0和k′+0,并加以比较.实验结果(k+0>k′+0)表明底物对酶被过氧化氢的抑制作用有一定保护作用.过氧化氢可能是通过氧化酶活性中心功能基团而导致酶活性的丧失.The effect of hydrogen peroxide on N-acetyl-β-D-glucosaminidase （NAGase） of mud crab （Scylla serrata） was investigated. The results showed that hydrogen peroxide （H2O2 ） can inhibit the enzyme activity obviously. The value of IC50, the inhibitor＇s concentration leading to 50% activity lost, was estimated to be 115mmol/dm^3. The inhibition of the enzyme by hydrogen peroxide is a reversible reaction with remaining enzyme activity. The inhibitory kinetics of the enzyme by hydrogen peroxide was studied using the Tsou＇s method of the substrate reaction, and the microscopic rate constants of inhibition for the free enzyme and the enzyme-substrate complex were determined. By comparison, it showed that k＋0 is larger than k＋0, indicating a marked protective effect of the substrate on the inhibition reaction of this enzyme by hydrogen peroxide.

关 键 词：锯缘青蟹 N-乙酰-Β-D-氨基葡萄糖苷酶 过氧化氢 抑制动力学 

分 类 号：Q356.1[生物学—遗传学]