Immobilization of soybean seed coat peroxidase on polyaniline: synthesis, optimization and catalytic properties.

MAGRI, M.L.; MIRANDA, M. V.; CASCONE, O.

BIOCATALYSIS AND BIOTRANSFORMATION

TAYLOR & FRANCIS LTD

Año: 2005 vol. 23 p. 339 - 346

1024-2422

Soybean seed coat peroxidase (SBP) was immobilised on various polyaniline-based polymers (PANI), activated with glutaraldehyde. The most reduced polymer (PANIG2) showed the highest immobilisation capacity (8.2 mg SBP/g PANIG2). Optimum pH for immobilisation was 6.0 and the maximum retention was achieved after a 6-h reaction period. Efficiency of enzyme activity retention was 82 %. When stored at 4ºC, the immobilised enzyme retained 80% of its activity for 15 weeks. The immobilised SBP showed the same pH-activity profile as that of the free SBP for pyrogallol oxidation and optimum temperature (55ºC) was 10ºC below that of the free enzyme. Michaelis-Menten experiments proved that Km was conserved while Vmax dropped from 82 to 1.6 mmol min-1 U-1. Substrate recognition ability was practically the same for both enzymes. Immobilised SBP showed a greatly improved tolerance (as compared with that of horseradish peroxidase) to different organic solvents, with only 30% inactivation at a concentration of 70% acetonitrile.