Isothermal titration calorimetry (ITC) is a versatile and easy to use technique
to study macromolecular interactions. Macromolecules interact with each other to
perform biochemical functions. These interactions are commonly based on proteinligand
binding interactions and may occur among peptide, DNA, RNA, lipid,
carbohydrate, ion, antibody, and enzymes. ITC experiments are relatively easy to
perform, and no labelling is required for the set up. Performing an ITC experiment not
only gives binding parameter but also it provides thermodynamic data. Further, the
thermodynamic data provides nature of the interaction at molecular level i.e. hydrogen
bonding, hydrophobic interactions.
Cooperativity of ligands and binding specificity of each site may be determined by this
technique. Molecular weight range, number of interacting molecules, and optical clarity
limit most of the instrumental techniques but ITC is not affected by these limitations.
All these benefits make ITC a common method to determine binding constants. A
combination of the technique with complementary methods augments its benefits in
detecting molecular mechanism.
Keywords: Binding constant, Dissociation constant, Drug design, Entropy,
Enthalpy, Food constituent analysis, Heat capacity, Protein-protein interaction,
Protein-receptor interaction, Stoichiometry.
