Immobilization of uricase upon polypyrrole-ferrocenium film

Abstract

In this study, uricase was immobilized by a glutaraldehyde/gelatine crosslinking procedure onto polypyrrole film. The Km value for immobilized enzyme 0.44 mM was much higher than that of the free enzyme 0.39 mM. Vmax values were 8.4 × 10-2 mM/dak and 7.1 × 10-2 mM/dak for free and immobilized enzyme, respectively. The optimal pH values for free and immobilized enzymes were 8.5 and 8.0, respectively. The optimum temperature for both free and immobilized uricase was 35°C and 55°C. The enzyme activity after storage for 7 weeks was found to be 42% and 49% of the initial activity values for free and immobilized enzymes, respectively. The amperometric current obtained after 30 measurements at a constant uric acid concentration of 5.0 × 10-5 M was found to be 77.7% of initial activity. Copyright © Informa Healthcare USA, Inc.