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

Abstract

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 (KYNA) on human (HSA) and bovine (BSA) 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 (ΔG⁰) change were calculated at different (10-35 C°) temperatures. Furthermore, the enthalpy (ΔH⁰), entropy (ΔS⁰) and heat capacity changes (ΔC_p ) of KYNA-protein complex formation were also calculated.