Isothermal Titration Calorimetry (ITC) is a technique used in quantitative studies of a wide variety of molecular interactions. It works by directly measuring the heat that is either released or absorbed during a molecular binding event.
ITC is the only technique that can simultaneously determine all binding parameters in a single experiment. Requiring no modification of binding partners, either with fluorescent tags or through immobilization, ITC measures the affinity of binding partners in their native states.
Measuring heat transfer during binding enables accurate determination of binding constants (KD), reaction stoichiometry (n), enthalpy (∆H) and entropy (ΔS). This provides a complete thermodynamic profile of the molecular interaction. ITC goes beyond binding affinities and can elucidate the mechanisms underlying molecular interactions. This deeper understanding of structure-function relationships enables more confident decision making in hit selection and lead optimization.
Isothermal Titration Calorimetry is used to measure reactions between molecules. The methodology allows determination of the binding affinity, stoichiometry, and entropy and enthalpy of the binding reaction in solution, without the need to use labels.
When binding occurs, heat is either absorbed or released and this is measured by the sensitive calorimeter during gradual titration of the ligand into the sample cell containing the biomolecule of interest.