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Design of a biosensor based on 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1H pyrrole

2010-07-01
Tuncagil, Sevinc
Varis, Serhat
Toppare, Levent Kamil
Immobilization of polyphenol oxidase (tyrosinase, E.C. 1.14.18.1) was achieved on a copolymer of 1-(4-nitrophenyl)-2,5-di(2-thieny1)-1H-pyrrole [SNS(NO2)] with pyrrole USNS(NO2)]/PPy) via electrochemical polymerization. Two different substrates; catechol and L-tyrosine were used for the characterization of biosensor. The kinetic parameters of the biosensor, maximum reaction rate of the enzyme (V-max) and Michaelis-Menten constant (K-m) were determined for two different substrates. V-max was found as 0.02 mu mol/min electrode for both substrates. K-m values were determined as 250 and 2 mM for catechol and L-tyrosine respectively. Calibration curves for enzyme activity versus substrate concentration were plotted between 0.05 and 0.5 M catechol and between 0.8 and 2.5 mM L-tyrosine. Optimum temperature and pH, operational and storage stabilities of immobilized enzyme were examined. (C) 2009 Elsevier B.V. All rights reserved,