Kinetic measurements of a surface confined redox reaction

Catalytic mechanism in successive two-step protein-film voltammetry—Theoretical study in square-wave voltammetry

“…This effect always exists in potential regions after the faradaic process occurs [14][15][16][17][21][22][23][24][25]32]. This phenomenon is typical for all catalytic mechanisms (EC′, or EEC′), while it does not exist by EC or CE systems [14,17,[22][23][24]33,[40][41][42]. When both electrochemical steps of the protein-film EEC′ mechanism are separated for 100 mV or more at the potential scale, then the kinetic and thermodynamic parameters of both redox steps, as well the rate constant of the catalytic reaction (i.e.…”

“…When both electrochemical steps of the protein-film EEC′ mechanism are separated for 100 mV or more at the potential scale, then the kinetic and thermodynamic parameters of both redox steps, as well the rate constant of the catalytic reaction (i.e. the Michaelis-Menten constant) can be estimated by exploring the methodologies elaborated and described in more details in our previous papers [17,30,39,41,42]. For the determination of the standard rate constants of electron transfer one can use the features of "quasireversible maximum" or "split SW peaks" [17,30,39].…”

Protein film voltammetry: electrochemical enzymatic spectroscopy. A review on recent progress

“…Over the last decade, significant efforts have been undertaken in modeling and simulations of the surface electrode processes, revealing that SWV is particularly appealing for mechanistic, kinetic, and thermodynamic characterization of surface electrode processes, including proteins and enzymes [27,[46][47][48][49][50][51][52][53][54][55]. So far, a plethora of electrode mechanisms have been considered, including simple surface electrode reactions [46,47,[56][57][58][59][60][61], surface reactions with uniform interactions [62], surface electrode reactions coupled with a preceding [63] or following chemical reaction [64], surface catalytic mechanisms [65,66], twostep surface reactions [67,68], and two-step reactions coupled with an intermediate chemical step (ECE -or electrochemical-chemical-electrochemical reaction scheme) [69]. The list of surface mechanisms can be easily extended, as the mathematical modeling of surface processes, although not easy, is yet simpler than in the case of common diffusion controlled processes.…”

Protein-film voltammetry: A theoretical study of the temperature effect using square-wave voltammetry

“…By Ψ red and Ψ ox we assign the cathodic (reduction) and anodic (oxidation) currents of the voltammograms, respectively. All these parameters of the voltammetric curves are mainly dependent on the potential modulation parameters (frequency-f, amplitude -E sw , and potential increment ΔE), as well as on the dimensionless redox kinetic parameter K, the number of exchanged electrons n, the electron transfer coefficient α, and the temperature T. Detailed studies of the features of simple surface redox reaction as a function of the kinetic parameter K, E sw , α, and n under conditions of square-wave voltammetry can be found elsewhere [2,19,20]. In this communication we only focus on the influence of the temperature to the main attributes of the square-wave voltammograms of a simple surface redox reaction.…”

“…This property is considered to be very useful for the determination of the standard rate constant of electron transfer, and it is discussed in detail in our concurrent paper (submitted). The most remarkable attribute of the simple surface redox reaction studied under conditions of square-wave voltammetry is the parabolic dependence of the dimensionless peak current on the magnitude of the kinetic parameter log(K) [2,20]. This feature is known as "quasireversible maximum", and it has been widely explored for estimation of the kinetics constant of electron transfer of various redox systems [5,20,22].…”