a Institute of Biochemistry and Biophysics, University of Tehran , Tehran , Iran .
J Biomol Struct Dyn. 2013 Dec;31(12):1440-54. doi: 10.1080/07391102.2012.742460. Epub 2012 Dec 19.
Catalase is an important antioxidant enzyme that catalyzes the disproportionation of H2O2 into harmless water and molecular oxygen. Due to various applications of the enzyme in different sectors of industry as well as medicine, the enhancement of stability of the enzyme is important. Effect of various classes of compatible as well as noncompatible osmolytes on the enzymatic activity, disaggregation, and thermal stability of bovine liver catalase have been investigated. Compatible osmolytes, proline, xylitol, and valine destabilize the denatured form of the enzyme and, therefore, increase its disaggregation and thermal stability. The increase in the thermal stability is accompanied with a slight increase of activity in comparison to the native enzyme at 25 °C. On the other hand, histidine, a noncompatible osmolyte stabilizes the denatured form of the protein and hence causes an overall decrease in the thermal stability and enzymatic activity of the enzyme. Chemometric results have confirmed the experimental results and have provided insight into the distribution and number of mole fraction components for the intermediates. The increase in melting temperature (Tm) and enzymatic rate could be further amplified by the intrinsic effect of temperature enhancement on the enzymatic activity for the industrial purposes.
过氧化氢酶是一种重要的抗氧化酶，它能催化 H2O2 歧化为无害的水和分子氧。由于该酶在工业和医学等不同领域的各种应用，提高其稳定性非常重要。本研究考察了各种类型的相容和非相容渗透剂对牛肝过氧化氢酶的酶活性、解聚和热稳定性的影响。相容的渗透剂脯氨酸、木糖醇和缬氨酸使酶的变性形式失稳，从而增加其解聚和热稳定性。与 25°C 时的天然酶相比，热稳定性的增加伴随着活性的轻微增加。另一方面，组氨酸是一种非相容的渗透剂，它稳定了蛋白质的变性形式，因此导致酶的整体热稳定性和酶活性下降。化学计量学结果证实了实验结果，并深入了解了中间体的摩尔分数成分的分布和数量。为了工业目的，通过温度对酶活性的内在增强作用，可以进一步放大酶的熔点（Tm）和酶反应速率的增加。
