Reaction Processes of Lipid-coated Enzymes in Supercritical Fluids

超临界流体中脂质包被酶的反应过程

基本信息

批准号：
11450311
负责人：
OKAHATA Yoshio
金额：
$ 9.09万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Supercritical fluids (scFs) have been attractive as media for enzymatic reactions, as well as other chemical reactions and media for extraction. Because their physical properties can be manipulated by small changes in pressure and temperature, and several of these properties (e.g., density, diffusiveness, and viscosity) are intermediate between those of gas and liquid. The larger diffusiveness in scF compared to a liquid can be expected to increase the reaction rate.In this report, we report the high catalytic activity of a lipid-coated b-galactosidase for transgalactosylation to alcohols in supercritical fluorofolm (scCHF3). Typical results are stummarized in the figure. A lipid-coated b-galactosidase can catalyse the transgalactosylation from p-nitrophenyl galactopyranoside to 5-phenylpentanol in sufficient efficiency in organic solvents, however the enzyme easily denatured and both the initial rate νo and the conversion decreased drastically in polar solvents above chloroform (the left figure). On the contrary, in the supercritical CHF3, the νo of the reaction increased 20 times compared with those in organic solvents (the right figure). The νo could be reversibly controlled by changing the pressure of supercritical fluid from 1 to 150 atm, and the conversion was almost constant, This means that the reactivity of a lipid-coated enzyme cam be reversibly controlled without denaturation in supercritical fluid by changing pressure (polarity). This is the first example to control enzyme reactions in supercritical fluids.

超临界流体（SCF）作为酶促反应的培养基以及其他化学反应和培养基以提取的吸引力。因为它们的物理特性可以通过压力和温度的较小变化来操纵，因此这些特性中的几种（例如，密度，可不同性和粘度）介于气体和液体之间。与液体相比，SCF的扩散性较大可以提高反应速率。在本报告中，我们报告了脂质涂层的B-半乳糖苷酶对超临界氟芬氏醇（SCCHF3）中酒精的催化活性高（SCCHF3）。典型的结果在图中被延伸。脂质涂层的B-半乳糖苷酶可以催化从硝基苯基半乳酰烷酰胺到有机溶液中足够效率的5-苯基戊二醇的经乳乳糖基化，但是该酶很容易变性，并且在极地含有极高的溶解度（Paller ofersplastional ostantatuce）中均降低了极度的降低，而对溶解剂的转化却大大降低了极化的含量（左上的铜）（左上的图形）。相比之下，在超临界框中，反应的νO与有机溶液中的反应增加了20倍（正确的图）。可以通过将超临界流体的压力从1到150 atm改变，并且转化率几乎是恒定的，这意味着可以通过变化压力（极性）将超临界流体的反应性控制不变，而不会在超临界流体中进行变性（极性）。这是控制超临界流体中酶反应的第一个例子。