Abstract

It is easy to understand that potential drugs must bind to their target structure. Therefore, the affinity of drug candidates to their target is tested: it is determined using increasing drug concentrations and at a specific timepoint. Although this procedure provides information on whether the drug binds its target, it completely neglects the fact that molecular interactions are not static. Rather, the binding is defined by continuous association and dissociation. The parameters of how fast a molecule binds (association rate) and how fast it dissociates (dissociation rate) are referred to as binding kinetics. As these kinetics impact on the efficiency of drugs or on the occurrence and severity of side effects, it is desired to screen drug candidates regarding their binding kinetics before proceeding with in vivo and clinical studies. Here, we present a microplate-based method that is suited to determine kinetic parameters not only in purified protein solutions, but also in cellular environments.