Application of a simple calorimetric data analysis on the binding study of cyanide ions by Jack bean urease

Cyanide ion was studied as an effector of Jack bean urease (JBU) at 300 K in 30 mmol/L Tris buffer, pH 7 by isothermal titration calorimetry (ITC). The simple novel model was used for CN− + JBU interaction over the whole range of CN− concentrations. The binding parameters recovered from the simple novel model were attributed to the cyanide ion interaction. It was found that cyanide ion acted as a noncooperative inhibitor of JBU, and there is a set of 12 identical and independent binding sites for CN− ions. The dissociation equilibrium constant is 750 μmol/L. The molar enthalpy of binding is ΔH = −13.6 kJ mol−1. The technique used provided an accurate and quick assessment of the effectiveness of the compounds to inhibit Jack bean urease.