根霉葡萄糖淀粉酶的复性复活动力学研究

本文利用荧光、紫外差光谱研究了根霉葡萄糖淀粉酶在盐酸胍变性后的复性、复活动力学。结果表明,该酶在小于4mol/L盐酸胍中变性是可逆的,其复性过程遵循一级反应方程。酶复活过程是由两个一级反应组成的复合反应,构象变化速度与复活过程中较快的反应速度相差无几,这可能是在Trp及Tyr微区的构象变化基本完成之后,酶活力恢复还没有完成造成的。

Studies on Kinetics of Glucoamylase From Rhizopus Sp, During Its Renaturation and Reactivition

The kinetics of the renaturation and reactivation of glucoamylase denatured by guanidine HCl was determined by means of the UV differential absorbance measurement and fluorescence emission spectra.The results showed that the process of denaturation of glucoamylase in less than 4mol/L guanidine HC1 solution was reversible and renaturation of the denatured enzyme followed the first order equation.If the renaturation rate was measured through the change of the relative fluorescence intensity of the enzyme, the rate constant will be k=5.10*********X10-3S-1.The process of reactivation was consisted of two first order equations, k1=1.10**********X10-3S-1 and k2 = 1.39********x10-4S-1(k1=8k2),respectively.The similarity between k and k1 led to the conclusion that the rate of conformational change was almost the same as that of the relatively fast step in renaturation.It indicats that the reactivation may have not completed even when the conformation of micro-environments of Trp/Tyr has basically formed.