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 mu mol/L. The molar enthalpy of binding is Delta H = -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. (C) 2009 G. Rezaei Behbehani. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.