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

Abstract

Immobilization of polyphenol oxidase (tyrosinase, E.C. 1.14.18.1) was achieved on a copolymer of 1-(4-nitrophenyl)-2,5-di(2-thienyl)-1 H-pyrrole [SNS(NO 2)] with pyrrole ([SNS(NO 2)]/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 μmol/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.