Isothermal Titration Calorimetry – An Overview
Interactions between biomolecules or macromolecules like proteins, nucleic acids, or lipids are essential for all cellular processes, ranging from replication, transcription, translation over protein biosynthesis and metabolism to signal transduction and cell-cell communication. The characterization of interactions between biomolecules is thus an important task in basic and applied life science, as well as in the pharmaceutical and biotech industry.
Every interaction between two molecules generates or absorbs heat, depending on the thermodynamic nature of the interaction. This heat change is measured in isothermal titration calorimentry (ITC) by titrating one interaction partner (usually present in a syringe) to the other interaction partner (usually present in a reaction cell). From the raw heat pulses binding isotherms are derived that deliver comprehensive information of the affinity, stoichiometry, and thermodynamics of molecular interactions.
ITC is widely used for quantifying binding affinity, for drug candidate selection, optimization, and validation, for measuring thermodynamics of molecular interactions, for confirmation of binding targets in small-molecule drug-discovery, for determination of binding specificity, or for validation of IC50 and EC50 values.