Kinetic studies of imidazole and its methyl derivative binding to metmyoglobin: Effects of substitute methyl on the binding affinity

The binding of imidazole and imidazole derivatives (4- and 2-MeIm) to the metMb was studied by 1H NMR spectroscopy to elucidate the effects of different methyl substitution positions on the affinity and kinetics of binding to metMb. These exogenous ligands can form stable complexes with metMb except 2-MeIm. Kinetics and equilibrium data for the binding of imidazole and 4-MeIm to metMb have been obtained by 2D EXSY, and the reasons for the different affinity are also discussed.