A Unified Framework of ECrevEC′ Mechanism in Protein-Film Cyclic Voltammetry: A Master Model for Mechanistic, Kinetic, and Thermodynamic Elucidation of Complex Redox Systems whose Electrode Transformation Takes Place from Adsorbed State

The interpretation of cyclic voltammetric responses of complex redox systems remains a major challenge, particularly for processes involving coupled chemical steps and catalytic regeneration. In this work, we introduce a comprehensive surface-confined ECrevEC′ mechanism that serves as a master theoretical framework capable of unifying a wide range of classical electrochemical mechanisms within a single simulation platform. The model describes two sequential electron-transfer steps separated by a reversible chemical transformation, followed by a regenerative catalytic step, all occurring under surface-controlled conditions.
Through systematic numerical simulations, we demonstrate that this generalized mechanism converges, under well-defined limiting cases, to simpler mechanisms including E, EE, ECrev, EC′, ECrevE, CrevE, and EEC′. The resulting voltammetric patterns exhibit rich features such as peak asymmetry, peak-to-peak separations, potential shifts and quasireversible maxima, and catalytic amplification, providing direct access to kinetic parameters (ks, kc, kcat), equilibrium constants (Keq), and thermodynamic constraints of the system.
Particular emphasis is placed on the applicability of the model in protein-film voltammetry (PFV), where immobilized redox-active biomolecules often undergo multi-step electron-transfer processes coupled with intramolecular rearrangements and catalytic cycles. The proposed framework enables rigorous interpretation of voltammetric data from lipophilic enzymatic systems, including quinone-based, flavin-based, and NAD(P)H-dependent redox pathways, offering new insights into their mechanistic complexity and interfacial behavior.