Thermodynamic studies on the interaction of cobalt with alpha-amylase

The interaction of cx-amylase from Bacillus amyloliquefaciens with divalent cobalt ion was studied by equilibrium dialysis and isothermal titration microcalorimetry methods at 27 degrees C in neutral solution at pH = 7.0. A new equation with a useful graphical method, very similar to the Scatchard plot was introduced to obtain a dissociation equilibrium constant using microcalorimetric data. The constant is remarkably like that obtained from a normal Scatchard plot, which uses equilibrium dialysis data. The enzyme activity increased significantly with an increasing concentration of cobalt; however, the temperature of denaturation of the enzyme decreased.