基于笼状配合物的酶可控封装及催化性能的研究

Immobilization of the enzyme is an effective way to improve the fragile nature of the enzyme and to realize the further application of the enzyme in the industry, so the synthesis and design of highly efficient enzyme-immobilized porous materials have attracted increasing interest from scientists. Covalent linkage and pore entrapment are two most efficient enzyme immobilization approach, however the research which focus on combining this two approach together for higher efficient enzyme immobilization is rare. Metal-organic cages are a type of porous material which have nanometer confined space, the ease of pore size tuning, richness of the structure, the potential of functional molecular capsules, can be potent supporting matrices for enzyme immobilization. Based on directional bonding strategy to design functional bipedal organic building block, we move our foucus to the encapsulation of different size enzyme into the confined space of M12L24, providing new idea and perspective for enzyme immobilization into porous materials, to research the interaction mechanism between enzyme and metal-organic cage. We expect through the regulation of the size and structure of the cage to encapsulate different size enzymes and achieve the enzyme catalytic performanc’s controllable adjustment, have a comprehensive understanding of similarities and differences between enzyme encapsulation into the confined space and enzyme immobilization outer the confined space, have a deep study of the effects of cage structure on the catalytic performance, establish the relationship of structure and properties, refer to function directional strategy to design and self-assemble more efficient enzyme-immobilized metal-organic cages.

对酶进行固定化是改善酶脆弱本性，实现酶在工业上进一步应用的有效途径，因而，合成和设计高效的酶固定化多孔材料是科学家们关注的焦点。共价连接和孔内封装是两种高效的酶固定化方法，但目前将这两种方法相结合实现更高效固定化的研究鲜有。作为主-客体主要研究对象，具有限域空间，构筑单元可功能化修饰的金属-有机笼状配合物，具备实现酶孔内封装和共价连接相结合的巨大潜力。本项目拟基于“定向成键”策略设计合成功能性双足有机构筑单元连接酶分子，自组装构筑笼的同时以超分子主体M12L24实现对不同尺寸酶限域空间内的可控封装，为酶的多孔材料固定化提供新的设计思路。通过对笼状配合物尺寸和结构的调控实现对不同尺寸酶的固定以及酶催化性能的调控，同时系统地对比酶在笼限域空间内封装和限域空间外固定化的异同，研究笼状配合物结构变化对酶催化性能的影响规律，建立结构和性能的构效关系，功能导向更高效酶固定笼状配合物的设计合成。

作为主-客体主要研究对象，具有限域空间，构筑单元可功能化修饰的金属-有机笼状配合物M12L24，具备实现酶孔内封装和共价连接相结合的巨大潜力。对酶进行固定化是改善酶脆弱本性，实现酶在工业上进一步应用的有效途径，因而，合成和设计高效的酶固定化多孔材料是科学家们关注的焦点。共价连接和孔内封装是两种高效的酶固定化方法，M12L24有望将两种方法相结合实现更高效固定化。项目结果表明，可以通过金属-有机分子笼的限域空间成功实现酶的可控封装，这有利于我们开展进一步的催化性能研究。在金属-有机分子笼内可控封装的MP-11（Microperoxidase-11, 微过氧化物酶-11）催化 3,5-二叔丁基邻苯二酚氧化的性能稍有提升，但效果差强人意，有进步和改善的空间。分子笼水溶性不好的问题限制了其在催化体系更好的应用，对金属-有机配体进行PEG链的修饰可成功得到水溶性的分子笼。将酶修饰于配体的内侧，形成酶可控封装的金属-有机分子笼，而后分子笼-聚合物（PolyMOCs）凝胶形成的同时利用聚合物链的修饰增加分子笼的分散性和水溶性；将酶共价修饰于功能有机配体的外侧，在PolyMOCs凝胶形成的同时将酶固定于凝胶的介孔内，实现酶固定化的同时利用分子笼的主-客体识别提高底物和辅酶的扩散，拓展酶在多孔材料固定化的设计思路。这种在分子笼的限域空间来可控封装酶的策略不仅丰富了酶固定化的方法，具有重要的理论意义。同时，酶因其分布较多的活性位点所带来的优异催化性能，使得它们具有潜在的应用价值。