Function and biotechnology of extremophilic enzymes in low water activity.
Function and biotechnology of extremophilic enzymes in low water activity.
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DOI：
10.1186/2046-9063-8-4
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发表时间：
2012-02-02
期刊：
影响因子：
--
通讯作者：
Dassarma S
中科院分区：
文献类型：
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作者：
Karan R;Capes MD;Dassarma S
极端微生物来源的酶通常在非标准条件下催化化学反应。这样的条件促进了聚集、沉淀和变性，降低了大多数非极端微生物酶的活性，这通常是由于缺乏足够的水合作用。一些极端嗜热酶保持一个紧密的水合壳，即使在液态水有限的情况下，例如在离子浓度较高的情况下，或在水接近冰点的低温下，也保持活性。极端嗜热酶能够通过改变竞争水合作用，特别是通过增加表面电荷和增加分子运动来改变其表面。这些特性使一些极端嗜热酶能够在非水有机溶剂中发挥作用，有可能设计出有用的催化剂。在这篇综述中，我们总结了极端微生物酶在高盐度和低温下发挥作用的知识现状，重点介绍了它们在低水活度下发挥作用的策略。我们讨论了对极端微生物酶功能的理解如何导致新一代酶催化剂的设计及其在生物技术中的应用。
Enzymes from extremophilic microorganisms usually catalyze chemical reactions in non-standard conditions. Such conditions promote aggregation, precipitation, and denaturation, reducing the activity of most non-extremophilic enzymes, frequently due to the absence of sufficient hydration. Some extremophilic enzymes maintain a tight hydration shell and remain active in solution even when liquid water is limiting, e.g. in the presence of high ionic concentrations, or at cold temperature when water is close to the freezing point. Extremophilic enzymes are able to compete for hydration via alterations especially to their surface through greater surface charges and increased molecular motion. These properties have enabled some extremophilic enzymes to function in the presence of non-aqueous organic solvents, with potential for design of useful catalysts. In this review, we summarize the current state of knowledge of extremophilic enzymes functioning in high salinity and cold temperatures, focusing on their strategy for function at low water activity. We discuss how the understanding of extremophilic enzyme function is leading to the design of a new generation of enzyme catalysts and their applications to biotechnology.