Isothermal Titration Calorimetry (ITC) binding services help researchers quantify molecular interactions directly in solution by measuring the heat released or absorbed during binding events. Unlike many indirect binding assays, ITC is label-free and can report multiple thermodynamic parameters in a single experiment—most notably binding affinity (Kd/Ka), stoichiometry (n), and enthalpy (ΔH), with entropy (ΔS) and free energy (ΔG) derived from the measured values. What ITC Measures (and Why It’s Different) At its core, ITC measures heat. When a ligand is titrated into a cell containing a binding partner (commonly a protein), each injection generates a heat signal proportional to how much binding occurs at that point in the titration. From the full binding isotherm, ITC can determine: Binding affinity: Kd (or Ka) Stoichiometry: n (how many ligand molecules bind per macromolecule, or binding-site equivalents) Enthalpy change: ΔH (measured directly) Gibbs free energy: ΔG (derived) Entropy contribution: ΔS (derived via ΔG = ΔH − TΔS) This combination matters because two interactions with the same Kd can be driven by very different physics—electrostatics/hydrogen bonding vs. hydrophobic effects, for example—often reflected in different ΔH and ΔS balances. What “ITC Binding Services” Typically Include While providers vary, ITC binding…
