Isothermal titration calorimetry (ITC)

Personnes ressources

Normand Cyr
Structural biology platform manager

Pascale Legault

Description of the technique

Isothermal titration calorimetry (ITC) is a biophysical technique used in the quantitative study of biomolecular interactions. The heat released or absorbed at the time of binding is measured directly, and allows for the simultaneous determination of all the thermodynamic parameters of the binding, as well as the affinity and the stoichiometry of the interaction. This measurement is carried out in solution, without prior modification of the partners.

Description of the equipment

MicroCal ITC200

The MicroCal iTC200 provides a detailed overview of the thermodynamic parameters of the binding reaction. The system has a 200 μl sample cell, and a 50 µl titration syringe, and allows direct measurement of the heat absorbed or released by mixing precise amounts of reagents during the experiment.

Data analysis is performed using Origin™ software, in which the user obtains the stoichiometry (n), dissociation constant (KD) and enthalpy (ΔH) of the interaction. The Origin software can also be used to fit more complex binding patterns (two sets of sites, competition binding etc.).

It is also possible to use the ITC control software to simulate an experiment and determine the optimal receptor and ligand concentrations to use.


  • MicroCal iTC200 Control Software
  • OriginLab Origin 7.0