Partially Purification and Characterization of Polyphenol Oxidase of Quince

Authors : Hülya YAĞAR, Ayten SAĞIROĞLU

Pages : 97-104

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Polyphenol oxidase insert ignore into journalissuearticles values(PPO, EC 1.14.18.1); was extracted from quince insert ignore into journalissuearticles values(Cydonia oblonga); by using 0.1 M phosphate buffer, pH 6.8. The polyphenol oxidase of quince was partially purified by insert ignore into journalissuearticles values(NH4);2SO4 and dialysis. Substrate specificity experiments were carried out with catechol, pyrogallol, L-DOPA, p-cresole and tyrosine. Catechol was the most suitable substrate compound for quince PPO. The Michaelis constants were 4.54 mM, 7.35mM and 17.8 mM for catechol, pyrogallol and L-DOPA, respectively at 25oC. The optimum pH and temperature were determined with the specific substrate catechol as 8.0 and 40oC, respectively. Of eight inhibitors tested L-cysteine, ascorbic acid and potassium cyanide were the most effective against quince PPO.
Keywords : Quince, polyphenoloxidase, purification, characterization