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 cytochro mes and spinach ferredoxin is described using cyclic and square-wave v oltammetry (SWV). No signals are detected when Nafion-coated electrode s are exposed to the protein solutions. In contrast, electrochemical r esponses 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) o f cytochrome c3. The stability of entrapped molecules upon repetitive cycling has been investigated. Such modified electrodes offer new pers pectives for studying proteins confined at electrode surfaces.