南极念珠菌脂肪酶 B (CALB) 是一种强大且易于表达的酶,广泛用于学术和工业实验室,具有多种不同类型的应用。在精细化学品生产中,实例包括外消旋仲醇和胺的酰化动力学拆分以及前手性二醇的去对称化(或反向水解反应)。然而,在酯的水解动力学拆分或酸的酯化动力学拆分(其中手性存在于底物的羧酸部分)的情况下,速率和立体选择性通常较差。在本研究中,基于迭代饱和诱变的定向进化被应用于解决后一个问题。相对于野生型 CALB,具有高度改进的活性和对映选择性的突变体被进化用于对硝基苯基 2-苯基丙酸酯的水解动力学拆分,选择性因子从 E = 1.2 (S) 增加到 E = 72 (S) 或恢复到E = 42 (R) 可选。令人惊讶的是,CALB 的酰基和醇袋中的点突变被证明是必要的。一些进化的 CALB 突变体在其他手性酯的动力学解析中也是有效的生物催化剂,而无需进行新的诱变实验。另一个值得注意的结果涉及发现α-取代羧酸酯的对映互补
p-Nitrophenyl esters carrying a chiral acyl group were synthesized. These compounds were shown to meet the requirements of chymotrypsin for the specific binding and the acylation. Therefore, the behavior of p-nitrophenyl esters with chymotrypsin is considered to be virtually identical to that of p-amidinophenyl esters with trypsin which were proposed as "inverse substrates" for the enzyme. These esters, derived from each pair of enantiomers, have been successfully used for the analysis of enantiomeric preference of chymotrypsin at the deacylation stage. The chiral requirement of the enzyme active site for the catalytic efficiency was discussed.
Laboratory Evolution of Enantiocomplementary Candida antarctica Lipase B Mutants with Broad Substrate Scope
作者:Qi Wu、Pankaj Soni、Manfred T. Reetz
DOI:10.1021/ja310455t
日期:2013.2.6
saturation mutagenesis was applied to solve the latter problem. Mutants with highly improved activity and enantioselectivity relative to wild-type CALB were evolved for the hydrolytic kinetic resolution of p-nitrophenyl 2-phenylpropanoate, with the selectivity factor increasing from E = 1.2 (S) to E = 72 (S) or reverting to E = 42 (R) on an optional basis. Surprisingly, point mutations both in the acyl and alcohol
南极念珠菌脂肪酶 B (CALB) 是一种强大且易于表达的酶,广泛用于学术和工业实验室,具有多种不同类型的应用。在精细化学品生产中,实例包括外消旋仲醇和胺的酰化动力学拆分以及前手性二醇的去对称化(或反向水解反应)。然而,在酯的水解动力学拆分或酸的酯化动力学拆分(其中手性存在于底物的羧酸部分)的情况下,速率和立体选择性通常较差。在本研究中,基于迭代饱和诱变的定向进化被应用于解决后一个问题。相对于野生型 CALB,具有高度改进的活性和对映选择性的突变体被进化用于对硝基苯基 2-苯基丙酸酯的水解动力学拆分,选择性因子从 E = 1.2 (S) 增加到 E = 72 (S) 或恢复到E = 42 (R) 可选。令人惊讶的是,CALB 的酰基和醇袋中的点突变被证明是必要的。一些进化的 CALB 突变体在其他手性酯的动力学解析中也是有效的生物催化剂,而无需进行新的诱变实验。另一个值得注意的结果涉及发现α-取代羧酸酯的对映互补
Iterative Saturation Mutagenesis Accelerates Laboratory Evolution of Enzyme Stereoselectivity: Rigorous Comparison with Traditional Methods
作者:Manfred T. Reetz、Shreenath Prasad、José D. Carballeira、Yosephine Gumulya、Marco Bocola
DOI:10.1021/ja1030479
日期:2010.7.7
Efficacy in laboratory evolution of enzymes is currently a pressing issue, making comparative studies of different methods and strategies mandatory. Recent reports indicate that iterative saturationmutagenesis (ISM) provides a means to accelerate directedevolution of stereoselectivity and thermostability, but statistically meaningful comparisons with other methods have not been documented to date
酶在实验室进化中的功效目前是一个紧迫的问题,因此必须对不同方法和策略进行比较研究。最近的报告表明,迭代饱和诱变 (ISM) 提供了一种加速立体选择性和热稳定性的定向进化的方法,但迄今为止尚未记录与其他方法在统计上有意义的比较。在本研究中,通过将 ISM 的功效应用于之前最系统地研究的定向进化酶,铜绿假单胞菌的脂肪酶作为手性酯立体选择性水解动力学拆分的催化剂,对其功效进行了严格测试。仅筛选 10,000 个转化体,就实现了前所未有的对映选择性 (E = 594)。
pH-indicator based assay for selective enzymes
申请人:ThermoGen, Inc.
公开号:US20020177180A1
公开(公告)日:2002-11-28
Provided herein is a method for the quantitative screening of hydrolase for desired substrate activity using pH indicators which are sensitive to the release of protons from a chemical reaction in a reaction mixture. The method comprises selecting buffer and indicator conditions such that both have the same affinity for protons such that the relative amount of buffer protonated is proportional to the amount of indicator protonated as the pH of the reaction mixture shifts. A reaction mixture is then prepared comprising a buffer, indicator, hydrolase to be tested, and desired substrate to be tested, allowing the hydrolase to react with the substrate. The reaction is monitored by detection of change in color of the reaction mixture, determined by the affect of the reaction on the indicator.