New Degenerate Metal-Oxide Electrodes for Nearly Reversible Direct Electron Transfer to the Redox Proteins

Published

April 1, 2002

Author(s)

Gintaras Valincius, Vytautas Reipa, M P. Mayhew, V L. Vilker

Abstract

Heavily doped cadmium tin oxide (CTO) film electrodes were developed for fast electron exchange with redox proteins. The metal oxide films showed nearly reversible electron transfer for the [2Fe-2S] proteins spinach ferredoxin (Sp fd) and putidaredoxin (Pdx), and the well-studied heme protein horse heart cytochrome c. These represent a family of proteins that are of comparable size, but vary significantly in overall charge, formal redox potential, and type of metal center. The unmediated electron exchange was achieved through variation of metal oxide film synthesis parameters that led to an increase of the charge carrier concentration up to the levels typical for degenerate semiconductors. In addition, the flat band potential of the films was shifted close to or more positive of the formal redox potentials of proteins such that the semiconductor electrodes would be utilized in an accumulation mode. The rates and sustainability of electron transfer for the two ferredoxins obtained on these cadmium tin oxide electrodes are as high or higher than previously reported.

Citation

Electrochemistry Communications

Volume

4

Issue

No. 4

Pub Type

Journals

Keywords

electron transfer, metal oxide electrodes, spinach ferredoxin

Citation

Valincius, G. , Reipa, V. , Mayhew, M. and Vilker, V. (2002), New Degenerate Metal-Oxide Electrodes for Nearly Reversible Direct Electron Transfer to the Redox Proteins, Electrochemistry Communications (Accessed October 10, 2025)