Direct electrochemistry of membrane-entrapped horseradish peroxidase. Part I. A voltammetric and spectroscopic study

This paper reports the electrochemical behaviour, relative to the Fe(III)-Fe(II) conversion, of horseradish peroxidase (HRP) entrapped within a solid matrix, at a pyrolytic graphite electrode. The results indicate that (i) immobilization enhances the electron exchange between the protein and the electrode surface; (ii) reversible electron transfer (eT) is achieved within a wide pH range (pH 3.0-12.0) even in the absence of mediators, (ii) the embedded protein shows native-like structural properties and increased stability. The results obtained may be of potential value, since they represent a first step for engineering a novel 'solid-state' electrode system, of importance for basic and applied biochemistry. (C) 1998 Elsevier Science S.A.