In biology, particularly in studies relating the structure of macromolecules to their functions, two of the most important questions are (i) how tightly does a small molecule bind to a specific interaction site and (ii) how fast does the reaction take place if the molecule is a substrate and is converted to a product? ITC is a quantitative technique that can determine the binding affinity (Ka), enthalpy changes (ΔH), and binding stoichiometry (n) of the interaction between two or more molecules in solution. ITC is now routinely used to directly characterize the thermodynamics of macromolecule binding interactions and the kinetics of enzyme-catalyzed reactions.
ITC has advantages over other techniques such as fluorescence assays, NMR and SPR for studying complex formation in terms of ease of use and cost. It does not require any fluorescent probes or radioactive tags for data analysis. Immobilization and chemical modification of protein is not required. Also, it does not have limitations associated with clarity of the solution, molecular weight, temperature or pH. It is one of the best methods for determining the thermodynamic parameters of ligand binding.
Reference: itc services