| Popis: |
Redox mechanisms in which a consecutive twostep electrode transformation occurs, and the product generated in the second electrochemical step at the electrode surface is coupled to a follow-up irreversible chemical reaction, is theoretically considered under conditions of square-wave voltammetry. The electrochemical description of considered systems is a “surface EECirr mechanism”. With the methodology named “protein-film square-wave voltammetry” we provide theoretical information on kinetics and thermodynamics of many lipophilic enzymes containing quinones or polyvalent cations of transient metals as redox active sites. We address theoretically situations of energetically separated square wave voltammetric peaks for at least 150 mV at potential scale. We also consider a complex scenario of a single voltammetric peak, hiding in its shape both the features of electrode steps (occurring at same potential) and the chemical reaction. We pay a particular attention on how to distinguish the surface two-step EECirr mechanism from a simple one-step surface ECirr mechanism, but also from other two-step surface mechanisms. While presenting plenty of calculated square-wave voltammograms relevant to many enzymatic systems, we point out several simple features that allow kinetic characterization of studied mechanism from time-independent experiments at constant scan rate. |
