Isothermal Titration Calorimetry (ITC) - CD BioSciences


Isothermal Titration Calorimetry (ITC)

Isothermal Titration Calorimetry (ITC)

Isothermal titration calorimetry (ITC) is a gold standard biophysical method for determining the thermodynamic parameters of molecular interactions in solution. This label-free technique directly measures the heat released or absorbed during a biomolecular binding event. It is commonly used to determine the binding of small molecules such as medical compounds to large macromolecules such as proteins.

In a signaling pathway, there are several components such as ligand, receptor, primary effector, second massager, secondary effecter and so on. It is crucial to determine the binding of a ligand and its receptors. For example, it is of great interest to discover which protein is an amino acid sensor in the mTORC1 signaling pathway.

With advanced technologies, CD BioSciences offers highly sensitive and flexible Isothermal Titration Calorimetry (ITC) services to make a complete thermodynamic profile of the biomolecular binding events in your interest.

General Principle of ITC

Isothermal Titration Calorimetry

Experiment Setting

A reference cell and a sample cell in a temperature-controlled compartment.

Parameter Measuring


Data Analyzing

Binding enthalpy(ΔH), binding affinity (Ka) and precise stoichiometry (n) can be determined through ITC. Free enthalpy of binding (ΔG) and binding entropy (ΔS) can be further calculated.

Advantages of ITC

  • Label-free
  • Either binding partners require no chemical modification, avoiding any influences of labels.

  • Immobilization-free
  • The measurements happen in solution. No immobilization of either binding partner is required.

  • Non-destructive
  • ITC measures the affinity of binding partners in their native states.

  • Wide Molecule Size
  • The molecular weight of reactants is not limited from small molecules to MDa.

  • Low Sample Consumption
  • Sample quantity can be as low as 300 µl with a concentration of 20 µM.

  • High Sensitivity
  • The binding constant can be as low as nM.

  • Spectroscopic Properties Irrelevant
  • The measurement is unaffected by the spectroscopic properties of reactants.

  • Complete Thermodynamic Profiling
  • ITC is the only technique that can simultaneously determine all binding parameters (binding affinity/ Ka, reaction stoichiometry/ n, enthalpy/ ∆H and entropy/ ΔS) in a single experiment. 

What ITC Tells

Isothermal Titration Calorimetry

Binding Thermodynamics 

Binding Enthalpy (ΔH)

Binding Entropy (ΔS)

Free Enthalpy of Binding (ΔG).

Steady-State Affinity 

Binding Affinity (Ka)

Interaction Stoichiometry

Precise Stoichiometry n (e.g. 1:1 or 2:1 binding)


In your research of cellular signaling pathways, are you still struggling to find the best way to determine the thermodynamic parameters of your biomolecular interactions? ITC is a highly efficient method for this purpose, which has been widely used to characterize the binding affinity of ligands and their receptors.

It can be used to analyze interactions between proteins, peptides, DNA, RNA, aptamers, small molecules, molecular fragments, ions, lipids, virus-like-particles, and artificial particles, such as

  • Protein-protein Interactions
  • Protein-DNA Interactions
  • Protein-RNA Interactions
  • Protein-small Molecule Interactions
  • DNA-small Molecule Interactions
  • RNA-small Molecule Interactions


CD BioSciences offers cost-effect, high quality and hassle-free isothermal titration calorimetry (ITC) services to our clients worldwide. We guarantee to deliver our results on time. Please feel free to contact us.

For research use only. Not intended for any clinical use.