A SIMPLE NOVEL METHOD FOR DETERMINATION OF AN INHIBITION CONSTANT BY ISOTHERMAL TITRATION MICROCALORIMETRY - THE EFFECT OF FLUORIDE-ION ON UREASE

A simple novel method was introduced for determination of an inhibitor binding constant (K-i) and enthalpy of binding by isothermal titratio n microcalorimetry technique. This method was applied to the binding o f fluoride ion, as an inhibitor, with the active sites of jack bran ur ease at pH = 7.0 (Tris 30 mM) and T = 300 degrees K. The dissociation equilibrium constant measured by this method was markedly consistent w ith the inhibition constant obtained from assay of enzyme activity in the presence of fluoride ion.