Principles of ITC assay

What is Isothermal Titration Calorimetry?

Isothermal Titration Calorimetry (ITC) is an analytical technique used in chemical thermodynamics to study molecular interactions in solutions, enabling the measurement of heat changes that are associated with binding events between biomolecules, such as proteins, nucleic acids, and small molecules. Through directly measuring the heat released, or absorbed, during these interactions, ITC assay provides valuable information regarding binding affinities, stoichiometry, and thermodynamic parameters.

ITC assay involves the addition of a ligand to a solution, as the ligand binds to the macromolecule, heat is released or absorbed. This heat results in thermal power, and the measurements are recorded by a calorimeter, generating a thermogram, this data will then be used to determine thermodynamic parameters.

Application of ITC assay in Drug Discovery

ITC assay is instrumental in the understanding and optimization of molecular interactions between drug candidates and their target molecules, therefore Isothermal Titration Calorimetry has a crucial role in key aspects of drug discovery, by providing quantitative data that will be used to advance discovery and development.

  • Binding affinities: Representing the degree to which a ligand binds to its target, ITC enables binding affinities to be determined, assessing the effectiveness of potential drug candidates and optimizing lead compounds.
  • Entropy: Measure of molecular disorder or randomness during a binding event between molecules, conformational changes, flexibility, structural rearrangements
  • Thermodynamic profile: Through ITC, data on the thermodynamic aspects of molecular interaction will be determined, such as information regarding enthalpy, entropy, and macromolecules. This provides insights into the driving force, stability, and energetics of these interactions, which will aid in the understanding of molecular mechanisms and optimizing the overall design of targeted therapeutics.
  • Environmental factors: ITC assay will be affected by environmental factors such as temperature, buffer composition and pH, sample concentration, and ionic strength, influencing experimental outcomes.
  • Stoichiometry determination:  Stoichiometry refers to the determination of the binding ratio between the ligand, and the target macromolecule, helping to understand the molecular recognition process.

Our Advanced ITC Assay Services

ITC is considered the preferred method in studying molecular interactions, as it offers several advantages over other biophysical techniques, with our ITC assay services, you will have access to:

Label-free detection: By preserving the native state of the biomolecules, ITC allows for label-free detection, providing an accurate representation of their interaction in physiological conditions. 

Quantitative Analysis: Quantitative data is provided through ITC on binding constants, enthalpy, entropy, stoichiometry, enabling precise characterization of molecular interactions, and providing quantitative data of various parameters.

Broad Applicability: ITC assay is highly versatile, and therefore it is applicable to a wide range of biological systems, it can analyze protein-ligand, protein-protein interactions, nucleic acid-ligand, and host-guest interactions, an invaluable tool for researchers across a variety of disciplines.

Minimal Sample Requirements: Only small amounts of a sample is needed for ITC assay study, making it suitable for precious or limited materials. This allows particularly advantageous studies to be conducted when working with rare or costly compounds, as it minimizes sample consumption, while delivering high-quality data.

High-Throughput Primary Screening via SPR


We offer SPR services for high-throughput fragment screening and hit validation, including fragment clean screens, binding level screens, and titration for binding confirmation and kinetics.

Isothermal Titration

Start your ITC assay study within 2 weeks of material receipt.

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