Oxygen- and temperature-dependent kinetic isotope effects in choline oxidase: Correlating reversible hydride transfer with environmentally enhanced tunneling
Oxygen- and temperature-dependent kinetic isotope effects in choline oxidase: Correlating reversible hydride transfer with environmentally enhanced tunneling
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DOI：
10.1021/ja0560377
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发表时间：
2005-12-21
影响因子：
15
通讯作者：
Gadda, G
中科院分区：
文献类型：
--
作者：
Fan, F;Gadda, G
胆碱氧化酶以甜菜碱醛为中间体，以氧为电子受体，催化胆碱氧化生成甘氨酸甜菜碱。本文研究了氧浓度和温度对氘代胆碱动力学同位素效应的影响。在饱和氧浓度下，1，2-[H-2（4）]-胆碱的D（Kcat/Km）和（D）k（cat）值与pH无关，而在高pH下，它们下降到极限值，该极限值取决于氧浓度，
Choline oxidase catalyzes the flavin-linked oxidation of choline to glycine betaine, with betaine aldehyde as intermediate and oxygen as electron acceptor, Here, the effects of oxygen concentration and temperature on the kinetic isotope effects with deuterated choline have been investigated. The D(Kcat/Km) and (D)k(cat) values with 1,2-[H-2(4)]-choline were pH-independent at saturating oxygen concentrations, whereas they decreased at high pH to limiting values that depended on oxygen concentration at