A density functional theory study on the catalytic mechanism of hydroxycinnamoyl‐CoA hydratase‐lyase |
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Authors: | Guangcai Ma Yulin Li Lixin Wei Yongjun Liu Chengbu Liu |
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Affiliation: | 1. Key Laboratory of Theoretical and Computational Chemistry in Universities of Shandong, School of Chemistry and Chemical Engineering, Shandong University, , Jinan, Shandong, 250100 China;2. Northwest Institute of Plateau Biology, Chinese Academy of Sciences, , Xining, Qinghai, 810001 China |
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Abstract: | Hydroxycinnamoyl‐CoA hydratase‐lyase (HCHL), a particular member of the crotonase superfamily, catalyzes the bioconversion of feruloyl‐CoA to the important flavor and fragrance compound vanillin. In this article, the catalytic mechanism of HCHL has been studied by using hybrid density functional theory method with simplified models. The calculated results reveal that the mechanism involves the hydration of the C?C double bond of feruloyl‐CoA and thence the cleavage of C? C single bond of β‐hydroxythioester. The hydration step is a typical concerted process, whereas C? C bond cleavage follows a concerted but asynchronous mechanism. The calculated energy barrier of hydration reaction is only slightly lower than that of cleavage process, implying both of two processes are rate limiting. By using three substrate analogs, the substrate specificity of HCHL was further examined. It is found that the p‐hydroxyl group of aromatic ring is necessary for the catalytic reaction. © 2013 Wiley Periodicals, Inc. |
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Keywords: | hydroxycinnamoyl‐CoA hydratase‐lyase density functional theory method catalytic mechanism substrate specificity |
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