The Stimulatory Effect of Various Salts on Yeast Alcohol Dehydrogenase Activity

Abstract

It has been known that enzyme activity is influenced by various factors such as temperature, pH,salts and pressure. However these effects are different for kind of enzyme. When we investigated the inactivation process of yeast alcohol dehydrogenase (YADH) by typical chemical denaturants, urea and GdmCl, we noticed that these effects are significantly different. The activity of YADH decreased gradually with increasing the urea concentration. On the other hand,the activity increased with increasing GdmHCl concentration up to 0.1~0.2 M, and it decreased at above 0.2 M GdmHCl. Also, the similar activation was observed in the solution adding only NaCl without the denaturing agent. From these result, it is clarified that the YADH activity is influenced by added salts. So, in this experiment, we discuss the relation between the activation of YADH and the kind of adding salts. When compared the activity change by anion and cation of same ionic radius, it was more influenced by anions than by cations. The significant difference was not observed among cations. When these salt effects were compared with various physical properties of salt, it is clarified that the concentration at maximum activity shows the good correlation with B-coefficient. Anion which has smaller B-coefficient shows the maximum of activity at lower ion concentration. Consequently our experiment clarified to have the influence by low concentration in anion as the large ion of B-cofficient which destructs the water structure. Therefore, it is suggested that the interaction between anion and enzyme is important factor for the activation of YADH by salts. Also, it is clarified that the negative hydration ions have effect on YADH activity at small amounts.