ITC(Isothermal Titration Calorimetry) Mr.Halavath Ramesh 16-MCH-001 Department of Chemistry Loyola College-Chennai University of Madras

Introduction Isothermal Titration calorimetry(ITC) is a physical technique used to determine the thermodynamic parameters of interactions in solution. It is most often used to study the binding of small molecules ( such as medical compounds) to larger macromolecules( Proteins,DNA etc..). ITC is a quantitative technique that can determine the 1. Binding Affinity(Ka) 2. Enthalpy Change (ΔH) 3. Binding Stoichiometry(n) 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 biomolecules of interest. This provides a complete thermo dynamic profile of the molecular interaction. Power difference is measured between the reference and sample cells. ITCs always try to maintain the temperature difference between reference and sample around zero. At the end of titration, when the macromolecules is saturated with ligand. No more binding occurs and only heat of dilution is observed.

The endothermic binding reaction can be measured in the ITC.

Isothermal Titration calorimetry (ITC) is a biophysical techniques that allows a thermodynamic characterization of an interactive system.