Catalytic activities associated with the enzymes II of the bacterial phosphotransferase system.
Catalytic activities associated with the enzymes II of the bacterial phosphotransferase system.
复制标题
与细菌磷酸转移酶系统的酶 II 相关的催化活性。
DOI：
10.1002/jss.400140303
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
SaierJr,MH
中科院分区：
文献类型：
--
作者：
SaierJr,MH
大肠杆菌中的磷酸转移酶系统(PTS)是一个多功能、多组分的酶系统。它的主要功能是碳源获取，而次要功能是调节细菌生理。该系统的主要功能包括(1)细胞外检测，(2)单向和交换跨膜运输，(3)依赖磷酸烯醇式丙酮酸和依赖糖磷酸的糖底物的磷酸化。次级功能包括(1)调节腺苷环化酶和各种非PTS酶的活性，以及(2)调节几种PTS酶的诱导合成。初级和次级功能似乎都是由糖底物与酶II复合体的结合引起的。其中一种完整的跨膜酶，甘露醇酶II(IImtl)，已经用洗涤剂溶解，纯化到均一，并在人造膜系统中重组。这种蛋白质IImtl的相对分子质量为60,000道尔顿。它具有胞外糖结合部位和明显的细胞内糖磷酸结合部位和磷酸化hPR结合部位。必需的巯基和抗体结合部位位于酶的胞浆表面，葡聚糖结合部位位于酶的外表面。初步实验表明，可以通过遗传和生化技术来剖析酶IImtls的不同功能。这些研究强调了PTS及其完整的膜蛋白成分的功能复杂性。
The phosphotransferase system (PTS) in Escherichia coli is a multifunctional, multicomponent enzyme system. Its primary functions deal with carbon source acquisition, while its secondary functions are concerned with the regulation of bacterial physiology. The primary functions of the system include (1) extracellular detection, (2) unidirectional and exchange transmembrane transport, and (3) phosphoenolpyruvate‐dependent and sugar phosphate‐dependent phosphorylation of the sugar substrates of the system. The secondary functions include (1) regulation of the activities of adenylate cyclase and various non‐PTS permeases and (2) regulation of the induced synthesis of several PTS enzymes. Both the primary and secondary functions appear to be elicited by the binding of a sugar substrate to an Enzyme II complex. One of these integral transmembrane enzymes, the mannitol Enzyme II (IImtl), has been solubilized with detergent, purified to homogeneity, and reconstituted in an artificial membrane system. The molecular weight of this protein, IImtl, is 60,000 daltons. It possesses an extracellular sugar binding site and distinct intracellular combining sites for sugar phosphate and phospho‐HPr. An essential sulfhydryl group and an antibody combining site are localized to the cytoplasmic surface of the enzyme, while a dextran combining site is localized to the external surface. Preliminary experiments suggest that the different functions of the Enzyme IImtlcan be dissected by genetic and biochemical techniques. These studies emphasize the functional complexity of the PTS and its integral membrane protein constituents.