Isothermal Titration Calorimetry (ITC) Detection Service

The core advantage of ITC lies in its capacity to directly measure binding heat signatures under near-native solution conditions. A single experiment simultaneously yields full affinity and thermodynamic parameters (KD, ΔH, ΔS, binding stoichiometry n). Unlike techniques that only output affinity values, ITC excels at elucidating binding mechanisms and comparing divergent binding driving forces across distinct compounds or protein mutants. It is especially well-suited for drug discovery, protein engineering, and in-depth molecular characterization projects.

ITC is applicable to a wide spectrum of molecular interaction systems, including protein–protein, protein–small molecule, protein–peptide, and protein–nucleic acid complexes. Particularly in small-molecule binding studies, ITC distinguishes enthalpy-driven versus entropy-driven binding events, delivering critical insights to guide compound optimization and structural modification. It also enables comprehensive interpretation for multi-site binding or complicated binding mechanisms.

Measurements of ultra-high-affinity interactions are inherently challenging, as titration curves saturate rapidly, narrowing the fitting window and yielding unstable parameters. To address this issue, we commonly reduce the effective binding strength — via competing ligand addition, lowered sample concentrations, or adjusted experimental workflows — to broaden the quantifiable affinity range and boost fitting reliability. For systems that remain incompatible with direct ITC detection, orthogonal techniques such as SPR can be adopted for complementary characterization.

Consistent buffer composition is extremely critical. Obvious differences between the buffer of the titrant and the analyte will generate strong background heat signals from dilution or ion exchange, which directly impair data quality. Dialysis or buffer exchange is generally recommended to place both substances in identical buffer systems, so as to obtain smooth baselines and titration curves suitable for fitting. In cases where complete buffer matching cannot be realized, blank control groups and optimized experimental design are required to eliminate background interference to the maximum extent.