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Immobilization of invertase, polyphenol oxidase and glucose oxidase n conducting copolymers of thiophene-capped polytetrahydrofuran and pyrrole

Böyükbayram, Ayşe Elif
Immobilization of invertase, polyphenol oxidase (PPO) and glucose oxidase (GOD) enzymes were performed in electrochemically synthesized two types of conducting copolymers. One end and two end thiophene-capped polytetrahydrofuran (TPTHF-1 and TPTHF-2) were copolymerized with pyrrole under conditions of constant potential electrolysis. The copolymers were characterized by thermal, spectroscopic and scanning electron microscopy analyses. Immobilization was carried out via entrapment of enzymes in two types of matrices during the copolymerization of pyrrole with the insulating polymers in the presence of sodium dodecyl sulphate (SDS). Kinetic parameters: Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined for the enzyme electrodes. Temperature optimization, pH optimization, operational stability and shelf-life of the enzyme electrodes were investigated. Enzyme electrodes of polyphenol oxidase and glucose oxidase were used to determine the amount of their substrates in samples. Polyphenol oxidase converts mono and diphenols to quinone. Amount of phenolic compounds in two kinds of wines were determined by analyzing the quinone amount. Glucose oxidase converts ?-D-glucose to D-glucono-1,5-lactone. Glucose amount was determined in two kind of factory-produced orange juices by analyzing D-glucono-1,5-lactone.