关键词: 佛手瓜, 多酚氧化酶, 相对活性, 抑制剂

Abstract:

Freshly-prepared crude polyphenol oxidase (PPO) from chayote was enzymologically characterized in the present study. Results showed that the optimal reaction pH and temperature for this enzyme were 7.5 and 30 ℃, respectively, and substrate concentration was positively correlated with enzyme activity. This enzyme could quickly catalyze the oxidation of pyrogallic acid as a substrate, but exhibited relatively low catalysis activity towards catechol, hydroquinone and resorcinol. The activity of this enzyme was inhibited by vitamin C, citric acid, sodium tetraborate, magnesium chloride and EDTA-2Na in decreasing order. With increasing concentration, there was an increase in inhibitory effects of vitamin C and citric acid against enzyme activity.

Key words: chayote fruits, polyphenol oxidase (PPO), relative activity, inhibitor