Effects of Urea on the Activity and Structure of Yeast Alcohol Dehydrogenase
1965 年 58 巻 1 号 p. 73-89
詳細
1965 年 58 巻 1 号 p. 73-89
The action of yeast alcohol dehydrogenase was inhibited reversibly by the presence of urea less than 2M. From kinetic data, it was assumed that urea does not compete with either substrate or coenzyme. The results of sedimentation analysis suggested that the reversible dissociation of the enzyme molecule into four subunits was caused by the presence of urea less than 2M. The enzymatic reac-tion, however, was inhibited irreversibly by concentrations of urea more than 2M. From measurements of ultraviolet difference spectra, fluorescence spectra and viscosity, the unfold-ing of the enzyme molecule was suggested to occur under these conditions. A good agree-ment was found between the change in protein structure and the irreversible loss of activity.
