Drug-Receptor Interaction Kinetics: A Case Study of Immobilized Endothelin Receptor A and Its Ligands

Abstract

The kinetic study in drug-receptor interaction analysis is of great significance for the efficacy and safety of a drug. In previous work, we established a one-step method to immobilize the endothelin receptor A (ETA) on the surface of macroporous silica gel through a covalent interaction between the epidermal growth factor tyrosine kinase (EGFR) at the C terminal of ETA and the covalent inhibitor ibrutinib. The affinity stationary phase was used for lead screening and investigating the thermodynamic binding of ligands and ETA. Herein, we intend to introduce the ETA column in the kinetic study of the receptor and three specific ligands (bosentan, macitentan, and ambrisentan) as well as three leads (ferulic acid, berberine, and palmatine) from herbal medicines. Three classical methods in affinity chromatography, nonlinear chromatography, peak decay, and peak profiling, were performed to determine the dissociation rate constants of the ligands to ETA. A comparison of the three methods was made and the binding parameters were discussed. The three methods gave the same order of the dissociation constants between the six ligands and ETA. The results indicated that the immobilized ETA can be used for not only thermodynamic studies but also kinetic investigations, which provides a reliable and fast evaluation for drug-receptor interaction analysis.