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.