Polyphenol oxidase potentials of three wild mushroom species harvested from Liser High Plateau, Trabzon

Crude enzyme extracts were prepared from Armillaria mellea (A. mellea), Lepista nuda (L. nuda) and Hypholoma fasciculare (H. fasciculare), which were harvested from the Liser High Plateau-Macka (Trabzon, Turkey). The crude polyphenol oxidase (PPO) extracts from each mushroom were highly active against 4-methylcatechol. Native polyacrylamide gel electrophoresis, stained by L-3,4-dihydroxyphenylalanine, showed the polyphenol oxidase potentials. The optimum pH value, for each enzyme, was 7.0. When enzyme extracts were incubated at pH 7.0 for 24 h at 4 degrees C, it was observed that L. nuda and H. fasciculare enzyme activities decreased by about 26% and 18%, respectively, but, A. mellea enzyme activity increased by about 11%. The temperature optima of A. mellea, L. nuda and H. fusciculare were, respectively, 30, 30 and 20 degrees C. Cr3+ and Cu2+ ions inhibited each activity. Also, sodium metabisulphite and ascorbic acid were strong inhibitors of the enzyme activities. (c) 2006 Elsevier Ltd. All rights reserved.