Biophysics of Macromolecules and their interactions / Technologies / Microcalorimetry
Contact: Sylviane HOOS
Microcalorimetry allows the thermodynamic characterization of interactions between molecules in solution, and multiple other biochemical reactions. Two types of calorimeters (manufacturer : Microcal, GE Healthcare) are available in the PFBMI, depending on the parameters that one wishes to measure
Isothermal Titration Calorimers (VP-ITC and ITC 200 models) are devoted to the study of molecular interactions. By measuring reaction heat changes at a constant temperature, the ITC instruments allow to directly determine the stoichiometry (n), the equilibrium constant (Ka), the enthalpy (ΔH) and entropy (ΔS) variations linked to binding reaction. Performing the analysis at different temperatures gives access to the heat capacity (ΔCp) variation that is associated with the molecular complex.
The Differential Scanning Calorimeter (VP-DSC model) is mainly dedicated to the measure of the thermal stability of macromolecules and their complexes. By measuring the heat capacity (ΔCp) variation at different temperatures, DSC allows a direct determination of the variations in enthalpy (ΔH) and entropy (ΔS), and of the half-transition temperature (Tm) that are associated with each structural transition. The pressure perturbation calorimetry (PPC) accessory, the first of its kind in France, allows to characterize volumetric properties of macromolecules, in particular their thermal expansion coefficient.