| 摘要: | 酵素因其高效催化特定反應的能力在工業上被廣泛應用，但也因為酵素在嚴苛環境下的不穩定性及催化完後難以與產物在反應溶液中分離，在使用上有許多限制。因此對於能增加酵素穩定性與實用性上的酵素固定化顯得格外重要且有潛力。本實驗室於2015年首次開發出以原位創新合成法，在水相室溫下以類沸石咪唑骨架材料ZIF-90封包過氧化氫?，利用金屬有機骨架材料的孔洞性，允許受質進入材料催化的同時又可以防止大分子蛋白質水解?的作用，提供紡織工業漂白水議題的解決辦法。又於2017年發表有關生物性複合材料更進一步的研究，金屬有機骨架材料對酵素提供空間侷限性的效果，降低酵素在展開劑尿素的環境下所造成結構展開及失活程度。然而因為類沸石咪唑骨架材料的小孔洞在受質和酵素的選擇上造成了限制。為拓展更大孔洞MOFs的綠色合成法，本實驗室緊接著於2019年利用機械力球磨法成功用UIO-66和Zn-MOF-74等大孔洞金屬有機骨架材料來包覆酵素，拓展了此類生物性複合材料的應用範圍。
雖然機械力球磨法只需要少量溶劑，而且合成時的能量傳遞非常有效率，是個非常不錯的綠色合成法，然而機械力球磨法運用在生物性複合材料的時候會遇到酵素因球磨時間增加而活性損失的情況。因此本篇論文致力於大孔洞MOFs水相常溫且綠色合成法，並將其運用於生物性複合材料，以利於研究大分子的生化現象。
本篇論文成功在生物友善且水相的環境下於十分鐘快速合成Zn-MOF-74並包封酵素，利用Zn-MOF-74一維且14 ?的大孔洞不但讓受質質傳更有效率，還可以減少空間侷限性對酵素的影響。大幅提升酵素固定化後之活性同時保有金屬有機骨架材料賦予酵素的尺寸篩選性，以避免酵素受到蛋白?的水解。並運用有較大受質的胰凝乳蛋白?展現Zn-MOF-74在生物性複合材料領域中擁有更廣的應用。
;Enzymes have been widely used in industrial applications due to their high efficiency and specificity in catalyzing reactions. However, there are lots of restrictions owing to their instability in harsh environments and their difficulty in separating from productions in the reaction solution. Therefore, it is particularly important and potential for enzyme immobilization that can increase the stability and practicality of the enzyme. In our previous report in 2015, we developed an innovative in-situ de novo synthesis method to encapsulate catalase with a zeolitic imidazolate framework-90, ZIF-90 a sub group of Metal-organic Frameworks (MOFs), at room temperature under aqueous in which MOFs is capable of protecting embedding enzyme from protease and maintaining its biological activity. In 2017 our laboratory published a further study on biocomposites. The MOFs is able to provide spatial confinement for enzymes, reducing the structural expansion under the environment of denature reagent, urea. However, the small pores of the zeolitic imidazolate framework limit the selectivity of enzymes and substrates.
Therefore, our laboratory had reported about encapsulating enzymes with large-pore metal-organic frameworks such as UIO-66 and Zn-MOF-74 via mechanochemistry, ball-milling, method in order to expand the applications of biocomposites.The ball-milling method only requires a few amounts of solvent, and the energy transfer during synthesis is very efficient, also it is a very green method. However, mechanochemistry has encountered problems such as enzymes slightly denatured during the ball milling process. To avoid this problem, and investigate the further study of large-pore metal-organic frameworks biocomposites, we look forward to developing a green synthesis method for obtaining MOFs with large-apeture under mild water-based at room temperature and extand more applications in industry. In this study, we found that CAT and CHT molecules can be encapsulated into Zn-MOF-74 materials, which has unique 1D hexagonal channels and nanometer-scale pore apertures, by using the de novo mild water-based approach under aqueous conditions at room temperature. The prepared CAT@Zn-MOF-74 and CHT@Zn-MOF-74 biocomposites retained the peroxidase and peptide digestion activities of CAT and CHT, respectively. The Zn-MOF-74 support provides an interesting size-sheltering effect and confers antiunfolding functions to CAT; it protects CAT from proteinase K and urea. This strategy not only provides a viable solution for developing biocomposites with better biocatalytic activities but also widens the spectrum of guests that can be embedded. As a pivotal first step, we firmly believe that the enzyme@MOF platform based on the de novo approach will pave the way for further applications owing to its extraordinary potential and performance. |
