Department of Biotechnology and Life Sciences, University of Insubria, via J.H. Dunant 3, 21100 Varese, Italy.
Int J Mol Sci. 2020 May 1;21(9):3206. doi: 10.3390/ijms21093206.
In nature, the D-enantiomers of amino acids (D-AAs) are not used for protein synthesis and during evolution acquired specific and relevant physiological functions in different organisms. This is the reason for the surge in interest and investigations on these "unnatural" molecules observed in recent years. D-AAs are increasingly used as building blocks to produce pharmaceuticals and fine chemicals. In past years, a number of methods have been devised to produce D-AAs based on enantioselective enzymes. With the aim to increase the D-AA derivatives generated, to improve the intrinsic atomic economy and cost-effectiveness, and to generate processes at low environmental impact, recent studies focused on identification, engineering and application of enzymes in novel biocatalytic processes. The aim of this review is to report the advances in synthesis of D-AAs gathered in the past few years based on five main classes of enzymes. These enzymes have been combined and thus applied to multi-enzymatic processes representing in vitro pathways of alternative/exchangeable enzymes that allow the generation of an artificial metabolism for D-AAs synthetic purposes.
在自然界中，氨基酸的 D-对映异构体（D-AAs）不用于蛋白质合成，并且在进化过程中在不同的生物体中获得了特定的和相关的生理功能。这就是近年来观察到对这些“非天然”分子的兴趣和研究激增的原因。D-AAs 越来越多地被用作构建块来生产药物和精细化学品。在过去的几年中，已经设计了许多方法来基于对映选择性酶生产 D-AAs。为了增加生成的 D-AA 衍生物，提高内在原子经济性和成本效益，并在低环境影响下生成工艺，最近的研究集中在识别、工程和应用新型生物催化过程中的酶。本文的目的是报告过去几年中基于五类主要酶的 D-AAs 合成的进展。这些酶已经被组合并应用于多酶反应中，代表了替代/可交换酶的体外途径，这些途径允许为 D-AAs 的合成目的生成人工代谢。
