ELECTRON-TRANSFER BETWEEN A QUINOHEMOPROTEIN ALCOHOL-DEHYDROGENASE AND AN ELECTRODE VIA A REDOX POLYMER NETWORK

A quinohemoprotein alcohol dehydrogenase (QH-EDH) from Comamonas testo steroni was immobilized on an electrode in a redox polymer network con sisting of a polyvinylpyridine partially N-complexed with osmiumbis-(b ipyridine)chloride. The enzyme effectively transfers electrons to the electrode via the polymer. An average maximum catalytic current of 11 mu A cm(-2) was observed with 1-propanol as the substrate. The maximum activity of the enzyme electrode (current density) for primary alcoho ls is independent of the type of substrate in contrast with the activi ty of the free enzyme. Affinity constants of the immobilized QH-EDH fo r different substrates are comparable with the values found for the fr ee enzyme. Typical half-lives for the immobilized enzyme electrodes ar e in the order of 5 h.