Abstract: The catalytic activity of polyphenol oxidase (PPO) from Agaricus bisporus towards the substrate catechol was spectrometrically investigated at 420 nm under the influences of temperature, pH, substrate concentration and heating time. The results showed that the optimal temperature, pH and substrate concentration for the reaction of the enzyme were 30 ℃, 5.5 and 0.05 mol/L, respectively. The complete enzyme activity was almost lost after 80 s of thermal treatment at 90 ℃. All four enzyme inhibitors investigated indicated inhibitory effects on the enzyme, especially ascorbic acid as the strongest factor, followed by citric acid, sodium chloride and EDTA-Na.

Key words: Agaricus bisporus, polyphenol oxidase, property