Microbial deracemization of α-amino acids
Microbial deracemization of α-amino acids
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DOI：
10.1016/j.molcatb.2004.12.002
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发表时间：
2005-02-01
影响因子：
--
通讯作者：
Ohta, H
中科院分区：
文献类型：
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作者：
Kato, DI;Miyamoto, K;Ohta, H
我们筛选了具有α-氨基酸去消旋活性的新微生物，并分离出一些活性菌株。这些菌株的全细胞能够将 4-氯苯丙氨酸的手性从 D-构型反转为 L-构型。特别是，Nocardia diaphanozonaria JCM 3208 对多种 α-氨基酸（如苯基甘氨酸和 2-氨基庚酸）表现出去消旋活性。对反应时间进程的检查表明，生成了 α-酮酸作为关键中间体。此外，使用无细胞提取物的机理研究表明，去消旋过程是通过两个酶促反应实现的； D-立体选择性氧化脱氨反应和L-选择性转氨反应。最后，我们可以建立利用无细胞系统进行苯丙氨酸去乙酰化的反应条件，当使用全细胞作为生物催化剂时，苯丙氨酸被降解。 (C) 2004 Elsevier B.V. 保留所有权利。
We screened new microorganisms having deracemization activity of alpha-amino acids and isolated some active strains. Whole cells of these strains were capable of inverting the chirality of 4-chlorophenylalanine from D- to L-configuration. In particular, Nocardia diaphanozonaria JCM 3208 exhibits the deracemization activity towards wide variety of alpha-amino acids, such as phenylglycine and 2-aminoheptanoic acid. Examination of the time course of the reaction revealed that alpha-keto acid was produced as the key intermediate. In addition, mechanistic studies using cell-free extract suggested that deracemization process is realized by two enzymatic reactions; D-stereoselective oxidative deamination reaction and L-selective transamination reaction. Finally, we could establish the reaction conditions utilizing the cell-free system to proceed the deracernization of phenylalanine, which was degraded when the whole cells were used as the biocatalyst. (C) 2004 Elsevier B.V. All rights reserved.