Definitions for "Dissociation constant"
The dissociation constant of an electrolyte such as a weak acid HA is a measure for the degree of dissociation of HA into H+ and A-. The dissociation constant is expressed as the product of the concentrations of the dissociated species divided by the concentration of the undissociated species : KHA = [H+] x [A-] / [HA] For more information click here
For systems in which ligands of a particular kind bind to a receptor in a solvent there will be a characteristic frequency with which existing ligand-receptor complexes dissociate as a result of thermal excitation, and a characteristic frequency with which empty receptors bind ligands as a result of Brownian encounters, forming new complexes. The frequency of binding is proportional to the concentration of the ligand in solution. The dissociation constant is the magnitude of the ligand concentration at which the probability that the receptor will be found occupied is 1/2.
number indicating the extent to which a molecule dissociates in solution to form free ions. For a simple two-component system (e.g.: CH3COOH CH3COO- + H+) it is the product of the molar concentration of the two ions divided by the molar concentration of the undissociated molecule: K = ([CH3COO-] x [H+]) / [CH3COOH]. The smaller the value of K, the less dissociation is present. K varies with temperature, ionic strength, and the nature of the solvent.
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For other uses see KD (disambiguation)
Tendency of a complex to dissociate. The smaller the Kd, the less likely is dissociation.