Comparison of Kinetics of Hemoglobin Electron Transfer in Solution and Immobilized on Electrode Surface

Abstract

The electron transfer properties of horse heart hemoglobin are compared using a hydrophilic indium tin oxide electrode and a dilaurydimethylammonium bromide (DDAB) polymer modified PG electrodes. A clear, stable and quasi-reversible redox curve of hemoglobin (Hb) was obtained in the absence of electron transfer mediators or promoters. The formal redox potential of -0.17 vs. Ag/AgCl of Hb was determined. The effects of the sixth axial binding ligands including cyanoand azido binding ligands on the redox properties of Hb were investigated. There are no significant impacts of these ligands on the redox properties of Hb, whereas big effects of the binding ligand on the electrochemical properties of myoglobin were reported. The cyclic voltammetric behavior of hemoglobin was also studied in a DDAB film coated on a pyrolytic graphite electrode. Surface immobilized Hb in DDAB film gave direct, quasi-reversible, nondiffusion-kinetic-controlled electron transfer on the electrode surface. The formal redox potential for Hb in the DDAB film negatively shifted about 140 mV as compared to the diffusion-controlled redox reaction of Hb.

Unlocking the Binding and Reaction Mechanism of Hydroxyurea Substrates as Biological Nitric Oxide Donors

“…In hypothesis B, the substrate radical will be retained in the active site through the stable hydrogen bonding interaction between H N′ and O Gly25 . Furthermore, adequate data in the literature − supports the plausibility of hypothesis B, in which various electron transfer reactions occur commonly either in solvent media or intra- or intertetramer subunits of hemoglobin. The complex array of hemoglobin electron transfer mechanisms indicates that an electron can easily be transferred to the hydroxyurea nitroxide radical to form the hydroxyurea nitroxide anion.…”

Direct Electron Transfer of Hemoglobin and Myoglobin at the Bare Glassy Carbon Electrode in an Aqueous BMI.BF4 Ionic‐Liquid Mixture

“…Almost all the works devoted to the study of direct electron transfer of Hb and Mb described an electrochemical behavior in relation with adsorption of the proteins onto the electrode surface (the electrode surface being or not being tailored to facilitate this adsorption) 24. 32, 33, 35 As an exception is the work of Taniguchi et al,31 which describes the fast direct electron transfer of horse‐heart Mb at a bare indium oxide electrode. Their cyclic voltammetry analysis revealed that the electron transfer was a pure diffusion‐controlled phenomenon.…”

Direct Electron Transfer of Human Hemoglobin Molecules on Glass/Tin-Doped Indium Oxide

“…i.e., surface roughness, crystallinity, and hydrophilicity [30], as well as the influence of the physiological milieu that was conditioned into the three-electrode cell system, charging positively/negatively to the working electrode (cf. Section 2.6 and Ref.…”