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首页> 外文期刊>Biotechnology Advances: An International Review Journal >Structural features of thermozymes.
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Structural features of thermozymes.

机译：热酶的结构特征。

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摘要

Enzymes synthesized by thermophiles and hyperthermophiles are known as thermozymes. These enzymes are typically thermostable, or resistant to irreversible inactivation at high temperatures, and thermophilic, i.e. optimally active at elevated temperatures between 60 and 125 degrees C. Enzyme thermostability encompasses thermodynamic stability and kinetic stability. Thermodynamic stability is defined by the enzyme's free energy of stabilization (DeltaG(stab)) and by its melting temperature (T(m)). An enzyme's kinetic stability is often expressed as its halflife (t(1/2)) at defined temperature. DeltaG(stab) of thermophilic proteins is 5-20 kcal/mol higher than that of mesophilic proteins. The thermostability mechanisms for thermozymes are varied and depend on the enzyme; nevertheless, some common features can be identified as contributing to stability. These features include more interactions (i.e. hydrogen bonds, electrostatic interactions, hydrophobic interactions, disulfide bonds, metal binding) than in less stable enzymes and superior conformational structure (i.e. more rigid, higher packing efficiency, reduced entropy of unfolding, conformational strain release and stability of alpha-helix). Understanding of the stabilizing features will greatly facilitate reengineering of some of the mesozymes to more stable thermozymes.
机译：由嗜热菌和超嗜热菌合成的酶称为热酶。这些酶通常是热稳定的，或在高温下对不可逆失活具有抵抗力，并且是嗜热的，即在60至125℃的高温下具有最佳活性。酶的热稳定性包括热力学稳定性和动力学稳定性。热力学稳定性由酶的稳定自由能（DeltaG（stab））和其解链温度（T（m））定义。酶的动力学稳定性通常表示为在规定温度下的半衰期（t（1/2））。嗜热蛋白的DeltaG（stab）比嗜温蛋白的DeltaG（stab）高5-20 kcal / mol。热酶的热稳定性机制是多种多样的，并取决于酶。但是，可以确定一些共同的特征来促进稳定性。这些特征包括比不稳定的酶更多的相互作用（即氢键，静电相互作用，疏水相互作用，二硫键，金属键合）和优异的构象结构（即更刚性，更高的包装效率，降低的展开熵，构象菌株释放和稳定性） α-螺旋）。对稳定特征的理解将极大地促进将某些介酶重新设计为更稳定的热酶。

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