Calorimetry is the science of measuring heat changes from chemical reactions or physical events.

Calorimetry relies on the fact that all chemical reactions involve a change in energy, usually accompanied by heat release (exothermic) or absorption (endothermic). Microcalorimetry is an ultrasensitive development of the technique that measures very small heat changes in small sample volumes, making it suitable for biomaterials.

Microcalorimetry is used to study reactions involving biomolecules, including interactions between molecules and conformational changes such as protein folding. Applications range from confirming intended binding targets in small molecule drug discovery to the development of stable biotherapeutics.

These processes are often studied using two calorimetric techniques: Isothermal Titration Calorimetry (ITC) and Differential Scanning Calorimetry (DSC).

Isothermal Titration Calorimetry (ITC)

Isothermal Titration Calorimetry (ITC) is used to study the binding behavior of biomolecules. It is an essential tool for drug design and the study and regulation of protein interactions.

ITC directly measures the heat released or absorbed during a biomolecular binding event. This allows accurate determination of binding constants (KD), reaction stoichiometry (n), enthalpy (∆H), and entropy (ΔS).

ITC is used for:

  • Quantify binding affinity.
  • Candidate selection and optimization.
  • Measurement of thermodynamics and active concentration.
  • Characterization of mechanism of action.
  • Confirmation of intended binding targets in small molecule drug discovery.
  • Determination of binding specificity and stoichiometry.
  • Validation of IC50 and EC50 values during hit-to-lead.
  • Measurement of enzyme kinetics.

Differential Scanning Calorimetry (DSC)

Differential Scanning Calorimetry (DSC) is a technique for understanding the stability of proteins and other biomolecules. It has wide application in protein engineering, rational drug design and biopharmaceutical production, where developing stable proteins is a critical goal.

DSC is a key thermal analysis technique that measures heat changes that occur in the biomolecule during a controlled increase or decrease in temperature, making it possible to study materials in their native state.

DSC enables:

  • Characterization and selection of the most stable proteins/potential candidates in biotherapeutic development.
  • Ligand interaction studies.
  • Rapid optimization of purification and manufacturing conditions.
  • Easy, rapid determination of optimum conditions for liquid formulations.
  • Quick stability-indicating assay for target proteins for use in screening.