Catalytic role of the calcium ion in GH97 inverting glycoside hydrolase
Catalytic role of the calcium ion in GH97 inverting glycoside hydrolase
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DOI：
10.1016/j.febslet.2014.07.002
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发表时间：
2014-08-25
期刊：
影响因子：
3.5
通讯作者：
Kimura, Atsuo
中科院分区：
文献类型：
--
作者：
Okuyama, Masayuki;Yoshida, Takuya;Kimura, Atsuo
通过结构和动力学研究，钙离子在糖苷水解酶家族97的转化酶BtGH 97 a的活性位点中的作用进行了研究。钙离子可能直接参与催化反应。在有或无钙离子存在下的k（cat）/K-m值的pH依赖性表明钙离子降低了碱催化剂的pK（a）。在不存在钙离子的情况下，具有碱性离去基团的底物的水解的k（cat）/K-m的显著降低证实了钙离子促进离去基团的离开。(C)2014年欧洲生物化学学会联合会。Elsevier B. V.出版，保留所有权利。
The role of calcium ion in the active site of the inverting glycoside hydrolase family 97 enzyme, BtGH97a, was investigated through structural and kinetic studies. The calcium ion was likely directly involved in the catalytic reaction. The pH dependence of k(cat)/K-m values in the presence or absence of calcium ion indicated that the calcium ion lowered the pK(a) of the base catalyst. The significant decreases in k(cat)/K-m for hydrolysis of substrates with basic leaving groups in the absence of calcium ion confirmed that the calcium ion facilitated the leaving group departure. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.