Complexity associated with caprylate binding to bovine serum albumin: Dimerization, allostery, and variance between the change in free energy and enthalpy of binding.

Isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), and pressure perturbation calorimetry (PPC) were used to study different aspects of the diverse interaction between the fatty acid caprylate and bovine serum albumin (BSA). The ITC thermogram was consistent with exothermic binding to a single site on BSA, which was electrostatic but had little or no hydrophobic contribution. ITC revealed that small changes to solution conditions and temperature were associated with apparent enthalpy-entropy compensation, causing large changes in enthalpy (ΔH) during binding, but with little corresponding changes in free energy (ΔG).