Isothermal Titration Calorimetry (lTC)

Isothermal Titration Calorimetry (lTC)


As a rapidly developing biophysical technique for studying molecular interactions in molecular biology and related fields, isothermal titration calorimetry (ITC) is the only method to directly measure the heat changes during complex formation at a constant temperature. It provides important information about molecular interactions such as binding constants, number of binding sites, free energy, enthalpy, and entropy simply by measuring the amount of heat absorbed or released when two solutions interact.

isothermal titration calorimetry (lTC) technologyFigure 1. Basic principle of isothermal titration calorimetry. (Song C, et al., 2015)

Working Principle

Forming ordered spatial structures or complexes of biomolecules such as proteins is a reversible thermally driven process. Whether it is an intramolecular or intermolecular biochemical reaction, there will be a certain degree of heat change before and after the reaction. ITC technology utilizes the principle of power compensation. It can accurately obtain the enthalpy change of intermolecular interactions occurring in a system over a wide range of concentration compositions through a single concentration scan to directly measure the heat change of the protein-ligand reaction and to fit the calculation of the binding thermodynamic parameters.


  • Does not interfere with the physiological functions of proteins and nucleic acids, with the unique advantage of non-specificity.
  • No constraints on the solvent properties, spectral properties, and electrical properties of the protein and nucleic acid systems under study.
  • Low sample dosage.
  • High sensitivity, no need to make a transparent and clear solution for measurement.

CD BioSciences has extensive knowledge of biophysics focused on isothermal titration calorimetry (lTC) for drug discovery and biomolecular interaction studies.

Main Applications

  • Biomolecular Interaction Research

We offer ITC techniques to obtain complete thermodynamic parameters of biomolecular interactions, including binding constants, number of binding sites, molar binding enthalpy, molar constant pressure heat capacity, and kinetic parameters (e.g., enzyme activity and enzyme conversion number).

  • Protein-protein Interaction Research

We utilize ITC technology to study protein folding or unfolding protein-small molecule interactions, and enzyme-inhibitor interactions. In addition, it can advance the study of enzymatic reaction kinetics and reveal drug-DNA/RNA interactions, protein-nucleic acid interactions, and biomolecule-cell interactions.

  • Drug Discovery

ITC can help us to confirm the expected binding target during small molecule drug discovery, while determining the thermodynamic properties and activity concentration, further accelerating the selection and optimization of drug candidates.

What Can We Offer?

CD BioSciences is deeply involved in the field of biophysical analysis and strives to provide isothermal titration calorimetry (lTC) services for drug discovery. If you are interested in our services and need more details, please feel free to contact us.


  1. Song C, Zhang S, Huang H. (2015). Choosing a suitable method for the identification of replication origins in microbial genomes[J]. Frontiers in microbiology. 6: 146676.
For research use only, not intended for any clinical use.
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CD BioSciences is a biotechnology company focused on biophysical services. We are proficient in both chemistry and biophysics, and have a comprehensive biophysical platform containing a wide range of advanced technologies.

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