Abstract:

Biocatalysis has the advantages in terms of sustainability, efficiency, selectivities and evolvability, thus it plays a more and more important role in green and sustainable synthesis, both in industrial production and academic research. However, compared with the well-known privileged chemocatalysts, enzymes suffer from the relatively limited types of reactions it can catalyze, which is unable to meet the future needs of green biomanufacturing. On the other hand, photocatalysis has emerged as one of the most effective strategies for the generation of reactive chemical intermediates under mild conditions, thereby providing a fertile testing ground for inventing new chemistry. However, the light-generated organic intermediates, including radicals, radical ions, ions, as well as excited states, are highly reactive resulting in the difficulties of controlling the chemo- and stereo-selectivities. The integration of biocatalysis and photocatalysis created a cross-disciplinary area, namely photoenzymatic catalysis, which can not only provide a new solution to stereochemical control of photochemical transformations with the exquisite and tunable active site of enzymes, but also open a new avenue to expand the reactivity of enzymes with visible-light-excitation. In addition, photoenzymatic catalysis inherits the inherent advantages of biocatalysis and photocatalysis, such as mild reaction conditions, representing green and sustainable synthetic methods. We have witnessed the booming development of photoenzymatic catalysis during the past several years. In this review paper, the recent advances in this field are highlighted. According to the cooperative modes of photocatalysis and enzymes, this paper is divided into following four parts: photoredox-enabled cofactor regeneration systems, cascade/cooperative reactions combining enzymes with photocatalysts, unnatural transformations with photoactivable oxidoreductase, and artificial photoenzymes. In this paper, we summarize the representative works and emphasize on the catalytic mechanisms of photoenzymatic transformations as well as the strategies for realizing abiological transformations. At the end of this review, by analyzing the challenges of photoenzymatic synthesis, the future directions are prospected. We hope that this review can inspire the discovery of more novel photoenzymatic systems and ultimately spur the applications of photoenzymes in industrial productions of high value-added enantiopure chiral products. {L-End}

Key words: enzyme catalysis, visible light catalysis, directed evolution, asymmetric catalysis, unnatural biotransformations

摘要：

酶催化具有绿色温和、高效高选择性的优势，在工业生产和技术研发等领域发挥着重要作用。然而，酶能催化的反应类型相对有限，难以满足未来绿色生物合成的需要。光催化已成为在温和反应条件下生成活性反应中间体的有效策略，但是光化学反应的选择性调控一直是个挑战性难题。结合光催化与酶催化的光酶催化合成，能够突破天然酶催化功能的局限，并为光化学领域的选择性调控难题提供新的解决方案，成为合成科学领域的研究热点之一。本文综述了光酶催化合成的最新研究进展，根据光酶的结合模式分成四部分讨论：光氧化还原实现辅因子再生、光催化剂-酶的协同或串联反应、光激发已知酶实现新转化、人工光酶。本文归纳了近年来光酶催化合成的代表性工作，重点分析光酶催化反应的化学机制和实现新生物转化的策略。与此同时，通过分析该领域当下面临的瓶颈，本文展望了光酶催化未来的发展方向，希望能够为光酶催化新转化的开发和更多高附加值化学品的绿色不对称合成提供参考。

关键词: 酶催化, 可见光催化, 定向进化, 不对称催化, 非天然生物转化