Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system. Evidence that the dimer is the active form of enzyme I.
Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system. Evidence that the dimer is the active form of enzyme I.
复制标题
大肠杆菌磷酸烯醇丙酮酸依赖性磷酸转移酶系统。
DOI：
10.1021/bi00546a009
复制
发表时间：
1980
期刊：
影响因子：
2.9
通讯作者：
G. Robillard
中科院分区：
文献类型：
--
作者：
O. Misset;M. Brouwer;G. Robillard
使用纯化的HPR、EI和来自大肠杆菌磷酸烯醇式丙酮酸依赖的糖运输系统的EII膜部分，进行了体外动力学测量。这些测量显示，甲基α-葡萄糖苷磷酸的形成有很大的滞后时间，这是EI和EII浓度的函数。滞后时间随EI浓度的增加而减小，但随EII浓度的增加而增加。在开始动力学测量之前，将EI与镁离子和磷酸烯醇式丙酮酸一起在37℃预孵化，可以减少或消除滞后时间。结果表明，滞后时间的原因是二聚激活EI的过程，这一过程受镁离子和磷酸烯醇式丙酮酸的影响。
In vitro kinetic measurements have been performed by using purified HPr, EI, and a membrane fraction of EII from the Escherichia coli phosphoenolypyruvate-dependent sugar transport system. These measurements reveal very large lag times in the formation of methyl alpha-glucoside phosphate which are a function of the EI and the EII concentrations. The lag times decrease with increasing concentrations of EI but they increase with increasing concentrations of EII. When EI, together with Mg2+ and phosphoenolpyruvate, is preincubated at 37 degrees C before starting the kinetic measurements, the lag time can be decreased or eliminated. We have shown that the process responsible for the lag time is the activation of EI by dimerization which is influenced by Mg2+ and phosphoenolpyruvate.