卤化酶催化机制及定向改造研究进展

Recent advances of halogenation mechanisms and halogenase engineering

摘要:

卤代化合物在农业化学、制药、材料等领域有着较高的应用价值，但是传统的化学合成手段往往使用有毒试剂，并可能引发环境污染问题。此外，传统方法还面临区域选择性和立体选择性不足的挑战，导致制备过程较为复杂。相比之下，酶促卤化技术因其高效的催化性能、温和的反应条件以及出色的区域和立体选择性潜力，被认为是绿色卤化工业中更具前景的选择。目前已经表征了多种卤化酶，包括遵循亲电芳香取代机制的亚铁血红素依赖型卤过氧化物酶、钒依赖型卤过氧化物酶和黄素依赖型卤化酶，遵循自由基机制的非血红素铁/α-酮戊二酸依赖型卤化酶和遵循亲核机制的S-腺苷-l-甲硫氨酸依赖型卤化酶。本文综述了各类卤化酶的关键活性位点与催化卤化机理，以及一系列为了提高其应用价值而进行的酶工程改造，最后简要讨论了其工业应用现状。作为一类有前景的生物催化剂，卤化酶可以高效地实现酶促合成及化学酶法合成多种卤代化合物，改善传统化学合成带来的环境污染问题，深入理解其催化机制与改造研究在合成领域具有重要的价值。

Abstract:

Halogenated compounds are widely used in agricultural chemical, pharmaceutical, and material industries. The chemical synthesis of these compounds ordinarily needs harsh conditions and noxious reagents, generating harmful by-products and products lacking regioselectivity. Halogenase-catalyzed halogenation with high efficiency, mild reaction conditions, outstanding stereoselectivity, and environmental friendliness demonstrates a promising prospect. Different types of halogenases have been characterized, including heme-dependent haloperoxidases, vanadium-dependent haloperoxidases, and flavin-dependent halogenases catalyzing electrophilic halogenation, non-heme iron/α-ketoglutarate-dependent halogenases catalyzing radical halogenation, and S-adenosine-l-methionine-dependent halogenases catalyzing nucleophilic halogenation. This review outlines the catalytic mechanisms of various halogenases and the engineering modifications for application and briefs the industrial application status of these enzymes. Halogenases can efficiently achieve enzymatic as well as chemoenzymatic synthesis of a variety of halogenated compounds, and significantly ameliorate the environmental issues caused by traditional chemical synthesis. Relevant mechanism and engineering research hold important value in the field of synthesis.