Characterization and potential applications of immobilized glucose oxidase and polyphenol oxidase

Pyrrole functionalized polystyrene (PStPy) was copolymerized with pyrrole to obtain a conducting copolymer, P(PStPy-co-Py) which is used as the immobilization matrix. Glucose oxidase and polyphenol oxidase enzymes were immobilized via the entrapment method by electrochemical polymerization. Enzyme electrodes were prepared by electrolysis at a constant potential using sodium dodecyl sulfate (SDS) as the supporting electrolyte during the copolymerization of PStPy with pyrrole. Maximum reaction rates (V-max) and enzyme affinities (Michaelis-Menten constants, K-m) were determined for the enzyme entrapped both in polypyrrole (PPy) and P(PStPy-co-Py) matrices. Optimizations of enzyme electrodes were done by examining the effects of temperature and pH on enzymes' activities along with the shelf life and operational stability investigations. Glucose oxidase enzyme electrodes were used for human serum analysis and glucose determination in two brands of orange juices. Polyphenol oxidase enzyme electrodes were used for the determination of phenolics in red wines of Turkey