Lookup NU author(s): Professor Mike Waring
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Drug-target binding kinetics are suggested to be important parameters for the prediction of in vivo drug-efficacy. For G protein-coupled receptors (GPCRs), the binding kinetics of ligands are typically determined using association binding experiments in competition with radiolabelled probes, followed by analysis with the widely used competitive binding kinetics theory developed by Motulsky and Mahan. Despite this, the influence of the radioligand binding kinetics on the kinetic parameters derived for the ligands tested is often overlooked. To address this, binding rate constants for a series of histamine H1 receptor (H1R) antagonists were determined using radioligands with either slow (low koff) or fast (high koff) dissociation characteristics. A correlation was observed between the probe-specific datasets for the kinetic binding affinities, association rate constants and dissociation rate constants. However, the magnitude and accuracy of the binding rate constant-values was highly dependent on the used radioligand probe. Further analysis using recently developed fluorescent binding methods corroborates the finding that the Motulsky-Mahan methodology is limited by the employed assay conditions. The presented data suggest that kinetic parameters of GPCR ligands depend largely on the characteristics of the probe used and results should therefore be viewed within the experimental context and limitations of the applied methodology.
Author(s): Bosma R, Soddart LA, Georgi V, Bouzo-Lorenzo M, Bushby N, Inkoom NL, Waring MJ, Briddon SJ, Vischer HF, Sheppard RJ, Fernandez-Montalvan A, Hill SJ, Leurs R
Publication type: Article
Publication status: Published
Journal: Scientific Reports
Online publication date: 27/05/2019
Acceptance date: 25/04/2019
Date deposited: 14/06/2019
ISSN (electronic): 2045-2322
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