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Immobilization of tyrosinase and alcohol oxidase in conducting copolymers of thiophene functionalized poly(vinyl alcohol) with pyrrole

2007-08-01
Yildiz, Huseyin Bekir
Sahmetlioglu, Ertugrul
Boyukbayram, Ayse Elif
Toppare, Levent Kamil
Yagci, Yusuf
Immobilization of tyrosinase and alcohol oxidase is achieved in the copolymer of pyrrole with vinyl alcohol with thiophene side groups (PVATh-co-PPy) which is a newly synthesized conducting polymer. PVATh-co-PPy/alcohol oxidase and PVATh-co-PPy/tyrosinase electrodes are constructed by the entrapment of enzyme in conducting copolymer matrix during electrochemical copolymerization. For tyrosinase and alcohol oxidase enzymes, catechol and ethanol are used as the substrates, respectively. Kinetic parameters: maximum reaction rates (V-max) and Michaelis-Menten constants (K-m) are obtained. V-max and K-m are found as 2.75 mu mol/(min electrode) and 18 mM, respectively, for PVATh-coPPy/alcohol oxidase electrode and as 0.0091 mu mol/(min electrode) and 40 mM, respectively, for PVATh-co-PPy/tyrosinase electrode. Maximum temperature and pH values are investigated and found that both electrodes have a wide working range with respect to both temperature and pH. Operational and storage stabilities show that although they have limited storage stabilities, the enzyme electrodes are useful with respect to operational stabilities. (c) 2007 Elsevier B.V. All rights reserved.