Electrochimica Acta, Vol.47, No.25, 4069-4077, 2002
Modified electrodes for probing the metal-reductase activity of metalloproteins: the reduction of iron(III) catalyzed by Desulfovibrio vulgaris Hildenborough cytochrome c(3)
Cytochromes c(3) are polyheme c-type cytochromes characterized by low redox potentials, that have been shown to develop metal-reductase activity. In this paper, different strategies are explored to immobilize one of them, Desulfovibrio vulgaris Hildenborough cytochrome c(3), a highly basic tetraheme cytochrome, including adsorption, covalent bonding, imprisonment in a layer-by-layer assembly, and entrapment within cast films or a dialysis membrane. The performance and efficiency of modified (carbon or gold) electrodes have been evaluated using electrochemical (cyclic and square-wave voltammetry, current-time curves) techniques in the presence of a soluble Fe(III) complex, ammonium Fe(III) citrate acting as the soluble substrate, and chosen as a model system. The advantages and drawbacks of each strategy are discussed with the view of further extension of environmental interest to more toxic metal contaminants.