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Updated: Aug 25, 2026

Isothermal Titration Calorimetry for Measuring Macromolecule-Ligand Affinity
Published on: September 7, 2011
Characterization of protein-protein interactions by isothermal titration calorimetry
Adrian Velazquez-Campoy1, Stephanie A Leavitt, Ernesto Freire
1Department of Biology and Biocalorimetry Center, Johns Hopkins University, Baltimore, MD, USA.
Abstract:
Isothermal titration calorimetry (ITC) is a powerful technique to study both protein-ligand and protein-protein interactions. This methods chapter is devoted to describing protein-protein interactions, in particular, the association between two different proteins and the self-association of a protein into homodimers. ITC is the only technique that determines directly the thermodynamic parameters of a given reaction: DeltaG, DeltaH, DeltaS, and DeltaCP. Isothermal titration calorimeters have evolved over the years and one of the latest models is the VP-ITC produced by Microcal, Inc. In this chapter we will be describing the general procedure for performing an ITC experiment as well as for the specific cases of porcine pancreatic trypsin binding to soybean trypsin inhibitor and the dissociation of bovine pancreatic alpha-chymotrypsin.
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