Cyanide ion was studied as an inhibitor of Jack bean urease at 300 K in 30 mmol/L tris buffer,pH 7.The inhibition was investigated by isothermal titration calorimetry(ITC).The extended solvation model was used for CN^- + JBU interaction over the whole range of CN^- concentrations.The binding parameters recovered from the solvation model were attributed to the cyanide ion interaction.It was found that cyanide ion acted as a non-cooperative inhibitor of urease,and there is a set of 12±0.12 identical and independent binding sites for CN^- ions.The dissociation equilibrium constant is 749.99μmol/L.The molar enthalpy of binding is△H=-13.60kJ mol^(-1).
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