ELECTRON-TRANSFER BETWEEN GALACTOSE-OXIDASE AND AN ELECTRODE VIA A REDOX POLYMER

Galactose oxidase from Dactyllium dendroides was purified and immobili sed on a carbon electrode in a redox polymer network of a polyvinylpyr idine, partially N-complexed with osmiumbis (bipyridine)chloride (POsE A). The current density of the electrodes depended on the concentratio n of phosphate elution buffer. By additional crosslinking with a 1% gl utaraldehyde solution in 50 mM phosphate buffer, pH 7.0, an electrode with an initial current density of 0.8 mA/cm(2) was obtained. Operatio nal half life times were in the order of 1.2 h. The affinity of the im mobilized enzyme for galactose,lactose, raffinose, glycerol and dihydr oxyaceton was higher than described in literature for the enzyme in so lution. Optimal temperature for the enzyme electrode was 30 degrees C. The pH optimum for the immobilized enzyme was higher than for the enz yme in solution.