茶多酚氧化酶酶学性质研究

On the enzymological feature of polyphenol oxidase from tea

采用柠檬酸—磷酸氢二钠缓冲液(pH 5.6)匀浆浸提法和硫酸铵沉淀法,从茶鲜叶中提取多酚氧化酶,并通过分光光度法研究pH,温度,抑制剂对酶活性的影响.结果表明:以邻苯二酚为底物,茶多酚氧化酶PPO的最适pH为5.6,最适温度为50℃,亚硫酸钠、半胱氨酸和V-C为PPO的抑制剂.

Polyphenol oxidase （PPO） was extracted from tea leaves with sodium phosphate buffer （pH5.6） and fractionated with solid ammonium sulfate. Spectrophotometer method was applied in the experiment to study the characters of PPO from tea, such as proper pH, optimum temperature and inhibitors. The results showed that when catechol was used as enzyme substrates, the proper pH was 5.6, the optimum temperature was 50 ℃, ascorbic acid, sodium sulfite, L-cysteine, benzoic acid and cinnamic acid were inhibitors of PPO from tea. Different substrates had different effects on PPO activity.