Calorimetric Measurement of SH2 Domain Ligand Affinities.

Isothermal titration calorimetry (ITC) has emerged as a leading approach in the characterization of protein/ligand interactions. This technique measures the heat change of a system upon binding of a ligand to a biomolecule, and thereby requires no immobilization, intrinsic fluorescence, or labeling of any kind of either species. If properly designed, a single experiment can not only measure the binding affinity, but also determine additional binding and thermodynamic parameters, including the enthalpy, entropy, and the stoichiometry of the interaction. Here, we describe the protocol for the collection of calorimetric data for the binding of peptides to SH2 protein domains.