Modelling and Characterization of the Sorption of Kynurenic Acid on Protein Surfaces

This paper presents a surface plasmon resonance (SPR) spectroscopy-based evaluation process which provides information on kinetic and thermodynamic aspects of the interactions between proteins and a drug molecule. Reversible binding of kynurenic acid (KYN Lambda) on human (HS Lambda) and bovine (BS Lambda) serum albumin-modified gold sensor surface has been investigated under physiological conditions at various temperatures. The SPR sensorgrams were fitted via nonlinear parameter estimation method by using pseudo first order kinetic model. Based on the concentration dependence of the estimated observed rate constants (k(obs)) the association (k(a)) and dissociation (k(d)) constants as well as the equilibrium constants (K-A) and the Gibbs free energy (Delta G(0)) change were calculated at different (10-35 C degrees) temperatures. Furthermore, the enthalpy (Delta H-0), entropy (Delta S-0) and heat capacity changes (Delta C-p) of KYNA-protein complex formation were also calculated.