Interaction Study of Bioactive Molecules with Fibrinogen and Human Platelets Determined by 1H-NMR Relaxation Experiments

In order to investigate the interaction processes between bioactive molecules and macromolecular receptors NMR methodology based on the analysis of selective and non-selective spin–lattice relaxation rate enhancements of ligand protons was used. The contribution from the bound ligand fraction to the observed relaxation rate in relation to macromolecular target concentration allowed the calculation of the normalized affinity index in which the effects of motional anisotropies and different proton densities have been removed. In this paper, we applied this methodology to investigate the affinity of epinephrine and isoproterenol towards two different systems: fibrinogen and platelets.