FB2026_03 , released September 17, 2026

CV Term Report

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General Information

Term

isothermal titration calorimetry

ID (Ontology)

MI:0065 (Molecular Interactions)

Definition

Isothermal titration calorimetry (ITC) measures directly the energy associated with a chemical reaction triggered by the mixing of two components. A typical ITC experiment is carried out by the stepwise addition of one of the reactants (~10-6 L per injection) into the reaction cell (~1mL) containing the second reactant. The chemical reaction occurring after each injection either releases or absorbs heat (qi) proportional to the amount of ligand that binds to the protein with a characteristic binding enthalpy (DH). As modern ITC instruments operate on the heat compensation principle, the instrumental response (measured signal) is the amount of power (microcalories per second) necessary to maintain constant the temperature difference between the reaction and the reference cells. Because the amount of uncomplexed protein available progressively decreases after each successive injection, the magnitude of the peaks becomes progressively smaller until complete saturation is achieved. The difference between the concentration of bound ligand in the ith and (i-1)th injections depends on the binding constant Ka and the total ligand injected. The calculations depend on the binding model (number of substrates). Analysis of the data yields DH and DG = -RTlnKa. The entropy change is obtained by using the standard thermodynamic expression DG = DH-TDS.[ PubMed:11785756 ]

Also Known As

"ITC" ; "itc"

Comment

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Full annotation statements	Interaction Groups
isothermal titration calorimetry (all annotations which use CV term, excluding "NOT" statements)

Spanning Tree (Parents/Children)

  experimental interaction detection
   |__biophysical
       |__isothermal titration calorimetry  102 rec.

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Relationships
Is a	biophysical
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Synonyms & Secondary IDs
Synonyms
	"ITC" EXACT PSI-MI-alternate "itc" EXACT PSI-MI-short
Secondary IDs

External Crossreferences & Linkouts