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

Abstract

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.

Interaction between myoglobin and hyaluronic acid in layer-by-layer structures—An electrochemical study

“…4-8. [7,14,31] and, in our case, the CV has an irreversible oxidation peak at ∼+0.3 V vs. SCE, which probably corresponds to oxidation of the free heme, as reported in [29]. Moreover, the oxidation peak does not increase in size with each deposition step, as would be expected and reported in [7,13,14], but slightly decreases.…”

“…Even though there is evidence of efficient myoglobin immobilization in layer- by-layer structures, without altering its properties and with direct electrochemistry occurring between the electrode and the protein [7,14,26,31], there are reports regarding heme release in LBL assemblies [27][28][29]. The cyclic voltammetric study was carried out taking into account the possibility of heme release, as well as or instead of direct electrochemistry of myoglobin [26], and can be seen in Figs.…”

“…In recent work, de Groot et al reported on heme release from myoglobin (Mb) immobilized in films of didodecyl dimethyl ammonium bromide (DDAB) [27,28] and in layer-by-layer assemblies of Mb with polystyrene sulfonate, both on pyrolytic graphite [29].…”

Direct electron transfer of myoglobin in mesoporous silica KIT-6 modified on screen-printed electrode

“…Electrochemical detection of H 2 O 2 possess many advantages including high sensitivity, strong selectivity and convenient testing, is significant in the clinical diagnosis, food quality control, industrial production and environment protection. Comparing with conventional cylindrical electrodes (glass carbon electrode [2,18], gold electrode [19], pyrolytic graphite electrode [20,21]), screen-printed electrode (SPE) is flake and can be used one-off, providing a good carrier to design miniaturized and potable H 2 O 2 biosensors.…”

Effect of Bioconjugation on the Reduction Potential of Heme Proteins

“…Little knowledge has been gathered about the redox properties of the protein prior to the lyophilization step, which could provide information about changes in the environment near the heme. Indeed, the formal reduction potential of the heme is rather sensitive to its chemical environment, which has been a source of controversy in the literature . The heme b cofactor is attached only via (noncovalent) proximal histidine ligation, and the distal site is not ligated by a protein-based residue.…”