Kinetic characterization of Rhodococcus ruber DSM 44541 alcohol dehydrogenase A
Kinetic characterization of Rhodococcus ruber DSM 44541 alcohol dehydrogenase A
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DOI：
10.1016/j.molcatb.2013.10.023
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发表时间：
2014-01-01
影响因子：
--
通讯作者：
Widersten, Mikael
中科院分区：
文献类型：
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作者：
Hamnevik, Emil;Blikstad, Cecilia;Widersten, Mikael
对生物催化和立体选择性醇脱氢酶在合成不对称催化中的应用的兴趣日益增加，激发了对潜在有用酶的详细研究，例如来自红球菌的醇脱氢酶A （ADH-A）。该酶能够催化对映体和区域选择性生产苯基取代的a-羟基酮（酰基酮），这是合成一系列生物活性化合物的前体。在这项研究中，我们已经确定了酶的活性选择苯基取代的邻二醇和其他芳基或烷基取代的醇和酮。此外，(R)-和(S)-1-苯乙醇氧化和苯乙酮还原的动力学机制被确定为一种以酶-辅酶二元配合物的构象变化为速率决定因素的Is theorel - chance （hit and run）机制。1-苯乙醇的(S)-对映体的270倍对映性的根本原因是r -对映体的非生产性结合。我们还表明，通过调节pH值来调整氧化还原化学的方向是可能的，当pH值大于7时，氧化反应更有利。(C) 2013 Elsevier B.V.版权所有
An increasing interest in biocatalysis and the use of stereoselective alcohol dehydrogenases in synthetic asymmetric catalysis motivates detailed studies of potentially useful enzymes such as alcohol dehydrogenase A (ADH-A) from Rhodococcus tuber. This enzyme is capable of catalyzing enantio-, and regioselective production of phenyl-substituted a-hydroxy ketones (acyloins) which are precursors for the synthesis of a range of biologically active compounds. In this study, we have determined the enzyme activity for a selection of phenyl-substituted vicinal diols and other aryl- or alkyl-substituted alcohols and ketones. In addition, the kinetic mechanism for the oxidation of (R)- and (S)-1-phenylethanol and the reduction of acetophenone has been identified as an Is Theorell-Chance (hit and run) mechanism with conformational changes of the enzyme-coenzyme binary complexes as rate-determining for the oxidation of (S)-1-phenylethanol and the reduction of acetophenone. The underlying cause of the 270-fold enantiopreference for the (S)-enantiomer of 1-phenylethanol has been attributed to non-productive binding of the R-enantiomer. We have also shown that it is possible to tune the direction of the redox chemistry by adjusting pH with the oxidative reaction being favored at pH values above 7. (C) 2013 Elsevier B.V. All rights reserved.