Specific ion effects on the electrochemical properties of cytochrome c

Abstract

The range of salts used as supporting electrolytes in electrochemical studies of redox proteins and enzymes 5 varies widely, with the choice of electrolyte relying on the assumption that the electrolyte used does not affect the electrochemical properties of the proteins and enzymes under investigation. Examination of the electrochemical properties of the redox protein cytochrome c (cyt c) at a 4,4'-bipyridyl modified gold electrode demonstrates that both the redox potential (E°') and the faradaic current are influenced by the nature of the electrolyte used, in a manner explained primarily by Hofmeister effects. The faradaic peak 10 currents display an atypical trend on switching from kosmotropic to chaotropic anions, with a maximum current observed in the presence of Cl -. For a series of cations, the peak current increased in the sequence;

Pentetic acid (DPTA) Cu(II) monolayer deposited on gold electrode—The base of biosensors for electrochemical screening of kinase JAK2 and potential inhibitor interactions

“…3A and B SI), which is consistent with the Hofmeister series [42]. A similar trend was observed for the electrochemical properties of cytochrome c studied in a range of different chloride salts [43]. The best Faradaic current was recorded in the presence of CsCl.…”

Effect of electrolytes on proteins physisorption on ordered mesoporous silica materials

“…The trend of the cation series at 0.2 and 0.5 M (Na + > Li + > K + > Cs + ) is not monotonic as that obtained for the anions, but shows a 'bell shape' as already observed for other protein systems[105][106][107][108]. Again, in this case a high salt concentration (0.8 M) leads to a less pronounced ion specificity.…”

Specific Ion Effects on the Mediated Oxidation of NADH

“…Nevertheless, in such bio‐electrochemical systems the chemical nature of the supporting electrolyte is not usually taken into account. Nevertheless, the supporting electrolyte in solution can affect the properties of enzymes and co‐enzymes in solution, affecting thermodynamic and kinetic parameters . For the redox protein cytochrome c (cyt c), changes in the redox potential (E0’) and Faradaic current have been described that depend on the nature of the ion in solution .…”

“…Nevertheless, the supporting electrolyte in solution can affect the properties of enzymes and co‐enzymes in solution, affecting thermodynamic and kinetic parameters . For the redox protein cytochrome c (cyt c), changes in the redox potential (E0’) and Faradaic current have been described that depend on the nature of the ion in solution . Protein physicochemical behaviour – i. e. aggregation, Brownian motion, electrophoretic mobility, surface charge, etc.…”