酵母乙醇脱氢酶胍变性时的失活与去折叠的比较研究

应用荧光发射光谱，圆二色光谱，二阶导数光谱和紫外差吸收光谱等监测手段，研究了酵母乙醇脱氢酶在胍溶液中的去折叠。比较不同盐酸胍浓度下酵母乙醇脱氢酶的失活与构象变化，实验表明酶的失活先于构象变化：在低浓度胍溶液中，构象尚未发生明显变化时，酶活几乎已经完全丧失。由上述结果可见，含有辅基金属离子Ｚｎ~（２＋）酶的活性部位较酶分子的整体结构也具有柔性。

A Comparison of Unfolding and Inactivation of Yeast Alcohol Dehydrogenase During Guanidine Denaturation

The unfolding process of yeast alcohol dehydrogenase during guanidine denaturation is studied by circular dichroism, second derivative spectra, fluorescence and ultraviolet differential spectroscopic methods. Comparison of inactivation and conformation changes during denaturation at the different concentrations of guanidine have clearly shown that inactivation as a whole occurs before noticeable conformational change of the enzyme molecule. At low concentrations of guanidine,the conformation change is hardly noticeable whereas the activity is almost entirely lost. The above results suggest that, comparing with the whole enzyme molecule, the active site which contains a zinc atom also has some flexibility, and further support the suggestion that the location of active site of the enzyme is limited in flexible molecular region.