Distinction between film loss and enzyme inactivation in protein-film voltammetry: a theoretical study in cyclic staircase voltammetry

Abstract

Inactivation of redox enzymes and the loss of enzyme’s material from its adsorbed film on electrode surface are events that have similar outputs when studied under conditions of protein-film voltammetry. In the current work, we present a series of novel theoretical results under conditions of protein-film cyclic staircase voltammetry that clearly reveal how to distinguish between these two events. Theoretical model elaborated in this work comprises a surface electrode mechanism in which the initial form of redox enzyme is involved in same time in an electrode transformation and in an irreversible reaction of deactivation. While a large set of theoretical voltammetric curves simulated at different conditions are discussed, we also give a tabular overview of some characteristic cyclic voltammetric patterns of this electrode mechanism. The simulated voltammograms can help the experimentalists to distinguish the phenomenon of loss of protein film from the electrode mechanism associated with enzyme deactivation. In addition, we give hints to apply suitable methodologies to get access to the kinetics of both steps involved in this electrochemical mechanism.Graphical abstract