Thermodynamic study on the interaction of Co2+ with Jack bean urease

The interaction of Jack Bean Urease with cobalt (II) ion was studied by Isothermal Titration Calorimetry (ITC) at 300 K and 310 K in 30 mM Tris buffer, pH=7. The stability of the enzyme increases due to its binding with cobalt ions. The extended solvation model was used to reproduce the heats of Co2++JBU interaction. It was found that there is a set of 12 equivalent and noninteracting binding sites for Co2+ ions. The association equilibrium constant and the molar enthalpy of binding are 4260.76M-1, -16.5 kJmol-1 at 300 K and 3438M-1, -16 kJmol-1 at 310 K, respectively.