New enzyme electrodes were fabricated by using carbon fiber as electrode substrate. Electrodes were obtained by immobilization of
invertase in the conductive polypyrrole matrix during electrochemical polymerization onto laboratory–made carbon fiber electrodes.
Maximum reaction rate, (Vmax) and substrate affinity, (Km), of immobilized enzyme were determined as 56.7 μmol min-1 electrode-1
and 1.57 mM respectively. The effect of conditions on enzyme activity was investigated. It was found that the optimum temperature,
optimum pH value, linear working range are 30 ºC, pH 5.0 and 0.0025−0.0200 M respectively. The electrodes were examined for
operational stability. The results were compared with the previous studies in which invertase was immobilized onto platinum substrate.