Immobilized horseradish peroxidase on discs of polyvinyl alcohol-glutaraldehyde coated with polyaniline

Abstract

Discs of network polyvinyl alcohol-glutaraldehyde (PVAG) were synthesized and coated with polyaniline (PANI) using glutaraldehyde as a chemical arm (PVAG-PANIG-HRP disc). The best conditions for the immobilization were established as about 1.0mgmL-1 of protein, for 60min and pH 5.5. The soluble enzyme lost all of its activity after incubation at 70C for 15min, whereas the PVAG-PANIG-HRP disc retained about half of the initial activity for pyrogallol. The same PVAG-PANIG-HRP disc was used consecutively three times without any activity lossbut presented 25 of the initial activity after the 7th use. PVAG-PANIG-HRP disc retained approximately 80 and 60 of its initial activity after 60 and 80 days of storage, respectively. Resorcinol, m-cresol, catechol, pyrogallol, -naphthol, naphthol, and 4, 4′-diaminodiphenyl benzidine were efficiently oxidized by the PVAG-PANIG-HRP disc (from about 70 to 90), and it was less efficient towards aniline, phenol, and 2-nitrosonaphthol. © Copyright 2012 Samantha Salomo Caramori et al.