ITC - Isothermal Titration Calorimetry

Please acknowledge the SIP core facility ( RRID: SCR_018986) in publications, on posters, or in talks if you use any instruments in the SIP core facility. Please include SIP's RRID (RRID: SCR_018986) and the grant numbers for instruments funded through instrumentation grants in your acknowledgements. This is a requirement from the funding agencies and is crucial for future funding. Find example text on the Acknowledgement Page or the individual instrument pages.

ITC - Isothermal Titration Calorimetry

ITC in in Biochemistry, Biophysics and Structural Biology

Isothermal Titration Calorimetry (ITC) is a widely utilised technique in biochemistry and biophysics for characterising binding reactions by directly measuring the heat produced or absorbed during binding. As a label-free, in-solution method, ITC operates under equilibrium conditions and does not require any modifications to the system being studied. This makes it a powerful and precise tool for investigating the thermodynamics of molecular binding, offering critical insights into a variety of biomolecular processes.

A key advantage of ITC is its ability to determine several thermodynamic parameters from a single experiment, such as the binding constant (Ka), stoichiometry (n), enthalpy change (ΔH), Gibbs free energy (ΔG), and entropy change (ΔS). By further analysing the temperature dependence of ΔH across multiple experiments, researchers can also calculate the change in heat capacity (Δcp). Beyond providing detailed thermodynamic data, ITC can also be used under specific conditions to examine enzyme kinetics, allowing for the determination of kinetic parameters such as the Michaelis constant (KM) and the catalytic rate constant (kcat). This comprehensive approach makes ITC a valuable tool for gaining a deeper understanding of enzyme function and molecular interactions

ITC data exsample for protein - small molecule binding

Key Highlights of Isothermal Titration Calorimetry (ITC) in Biology, Biochemistry, and Biophysics

  • Measure binding heat directly
  • KD, ΔH, ΔG, ΔS, Δcp (protein-protein, protein-ligand, DNA/RNA-ligand, DNA/RNA-protein, protein-lipids, peptide-lipids...)
  • Affinity range:  10-­3 to 10-8 M
  • No coupled enzyme assay, standard curves, labelling or immobilization needed
  • Works in turbid or coloured solutions
  • Can determine multiple binding affinities and stoichiometries in one system
  • Enzyme kinetics, KM, kcat (in some cases)
  • Inhibitor studies, KI
  • Folding reactions (proteins, RNA, DNA)
  • And more... 
ITC 200

Instruments and Accesories

  • ITC200 (Microcal), lowest sample volume
  • VP-ITC (Microcal), highest sample volume, slightly higher sensitivity
  • Affinity ITC (TA instruments), low sample volume in manual mode, comparable to ITC200, equipped with autosampler, use of autosampler increases sample volume drastically because of connection dead volume.

Essential Information for Using SIP's ITCs

Acknowledgements Protocols Training Scheduling Cost Location
Acknowledgements

Why?

Acknowledgements are essential for ensuring the continued success of the Shared Instruments Pool (SIP). They enable us to secure the necessary funding to sustain and expand the SIP, ensuring that our instruments are in optimal working condition and that the methods we offer are at the forefront of biochemical and biophysical research.

Please include SIP's RRID number (RRID: SCR_018986) in your acknowledgements. This allows funding organisations and potential grant reviewers to easily locate publications supported by SIP, helping to evaluate the impact of SIP on our research community.

If facility staff have provided substantial assistance, please consider acknowledging them. If they contributed significantly to the intellectual aspects or conducted important experiments, co-authorship may also be appropriate.

Example text:

  • We thank the Shared Instruments Pool (RRID: SCR_018986), Department of Biochemistry, University of ÃÛÌÇÖ±²¥ Boulder for the use of the ITC 200 (Microcal). The ITC 200 was funded by NIH S10RR026516. We also thank [Name and title of the facility member providing significant help] for their invaluable assistance with data collection and evaluation.
  • We thank the Shared Instruments Pool (RRID: SCR_018986), Department of Biochemistry, University of ÃÛÌÇÖ±²¥ Boulder for the use of the Affinity ITC (TA). We also thank [Name and title of the facility member providing significant help] for their invaluable assistance with data collection and evaluation.

Please contact Dr Erbse to obtain detailed protocols and arrange an initial project consultation and personalised training sessions. Protocols are available as PDF files on the instrument computer, with printed copies stored alongside the instruments.

Interested users can contact Dr Erbse to discuss planned experiments and arrange training sessions. These sessions will involve the use of actual user samples alongside standards, enabling users to collect preliminary data during the training and receive help from core staff right away if troubleshooting or optimisation is needed. Users are welcome to request additional training or support sessions at any time. We are always happy to provide a refresher if it has been a while.

After the training is completed, users will be invited to join the ITC Google calendar for the ITC they were trained on.

Sign Up Rules: 
Up to Friday the week before the planned experiment users can sign up for a maximum of 2 days. In the week of the experiment users can sign up for additional time if available.

  • Initial consultation is free. SIP staff are happy to assist with a short pilot experiment if it can be accommodated within SIP's resources.
  • Regular user groups are expected to buy into SIP with a monthly flat fee according to their SIP usage level. For detailed information, please contact Dr Annette Erbse.
  • Users are required to provide all consumables specific to their experiments.
  • Costs for necessary repairs, services, or replacement parts due to normal wear and tear will be shared among all user groups, based on the time used over the past two years. Please note that assuming the instrument is handled properly, such repairs or replacements are infrequent, and costs may arise after a user’s period of use has ended.
  • Users are responsible for covering the costs of repairs or replacement parts needed due to damage caused by carelessness or neglect.
  • The ITC200 is located on the fourth floor of JSCBB in the A-Wing, room A454, on East Campus. Proxcard access is required at all times.
  • The VP-ITC is located on the third floor of JSCBB in the D-Wing, room D381, on East Campus. Proxcard access is required at all times.
  • The Affinity ITC  is located on the first floor of JSCBB in the D-Wing, room D180, on East Campus. Proxcard access is required at all times.