ELECTROCHEMICAL-BEHAVIOR OF REDOX PROTEINS ENTRAPPED IN NAFION FILMS

Several redox proteins are studied at Nafion-coated pyrolytic graphite (PG) electrodes. electrochemical behavior of polyheme c-type cytochromes and spinach ferredoxin is described using cyclic and square-wave voltammetry (SWV). No signals are detected when Nafion-coated electrodes are exposed to the protein solutions. In contrast, electrochemical responses are observed when droplets of protein solutions, deposited on the PG surface are dried then entrapped in Nafion layer. These Nafion-modified electrodes permit one to detect very small amounts (1 mug) of cytochrome c3. The stability of entrapped molecules upon repetitive cycling has been investigated. Such modified electrodes offer new perspectives for studying proteins confined at electrode surfaces.