Isothermal titration calorimetry (ITC)
Isothermal titration calorimetry (ITC) is used in thermodynamic analyses of macromolecular interactions. This technique is often referred to as a true in-solution method, as it does not require chemical tagging or immobilization of the interacting components. The measured heat, either absorbed or released upon binding, provides the basis for determination of:
1. binding constants (Ka)
2. enthalpy (ΔH)
3. entropy (ΔS)
4. stoichiometry of the reaction.
Common applications include analysis of protein interactions with another protein, peptide, metal, or nucleic acid.
Microcal VP-ITC calorimeter
The MicroCal VP-ITC is a highly sensitive calorimeter that allows for analysis of dilute solutions of macromolecules (typically in the micromolar range for proteins). The instrument sample cell volume is approximately 1.5 mL, with the injection syringe containing about 290 µL of titrant. The isothermal operation is carried out within the temperature range of 2oC to 80oC.