金属酶中双氧活化的模型研究及应用

Models in Metalloenzymes for Dioxygen Activation

金属酶活化双氧的过程对生物体内新陈代谢、信号转导等一系列功能至关重要。生物体内实现双氧活化功能的金属酶主要有血红素酶和非血红素酶两类。对模型化合物催化双氧活化过程中间体的表征及催化反应产物的分析可以揭示金属酶的双氧活化机理;对模型化合物的反应活性与配体电子效应的研究将为配合物催化剂的配体设计提供指导。特别是血红素酶和非血红素酶可以实现对C—H键的选择性活化,这是化学反应的难题之一。因此这些模型化合物可以被用做催化剂来解决药物发现、工业生产以及能源转化中的难题。本文介绍了血红素酶和单核非血红素酶模型化合物在机理研究上的近期进展,分析了卟啉类似物、二组氨酸一羧酸面式结构酶模型化合物等模型的设计思想和高价金属氧合中间体的电子结构,总结了配体电子效应和模型化合物催化活性之间的关系。最后,提出了目前模型化合物在双氧活化研究中存在的一些不足,并对其在基础研究及应用方面的发展进行了展望。

Metalloenzyme catalyzed dioxygen activation is a key process for many metabolisms and signal transmissions in bio-systems. Heine enzymes and non-heme enzymes are the two groups with the dioxygen activation functions. Model compounds of these enzymes are introduced into catalyzed reactions to illustrate the mechanisms of dioxygen activation through characterizations of intermediates and final products. Study on reactivity and electronic effects of the model compounds can guide the design of novel catalysts. Besides, some heme enzymes and non-heme enzymes can selectively activate C--H bonds, which is a difficult transformation in chemistry. Thus, these model compounds can be applied as catalysts to overcome some ineradicable difficulties in drug discovery, chemical engineering and energy transformation areas. This review introduces the recent development in mechanism study on dioxygen activation of heme and non-heme enzymes. The design of porphyrinoid and 2-His-1-carboxylate facial triad models, and the electronic structures of high-valent metal-oxo complexes are analyzed. The relationship between reactivity and the electronic effects of ligands in models is summarized. In addition, some existing problems in the area and prospects of enzyme model compounds in research and further applications are also proposed in this review.