Evidence for heme release in layer-by-layer assemblies of myoglobin and polystyrenesulfonate on pyrolitic graphite

Layer-by-layer assemblies of myoglobin and polystyrenesulfonate (PSS) on pyrolitic graphite have been investigated with the goal of determining the origin of the voltammetric response of these films. From the similar midpoint potential, coverage and electron transfer behavior compared with those of adsorbed free heme, it was concluded that the observed voltammetric peak is due to heme adsorbed at the electrode surface. This suggests that the interactions between the pyrolitic graphite electrode, PSS and myoglobin can result in heme release from the protein followed by heme adsorption on the electrode.