摘要
以邻苯二酚为底物,采用分光光度法在420nm处测定蜜柚多酚氧化酶(PPO)的活性,研究底物浓度、pH、温度及酶液浓度对PPO活性的影响,并建立了酶促褐变反应动力学方程。结果表明:蜜柚多酚氧化酶的酶促反应符合米氏方程所描述的单底物酶促反应动力学,以邻苯二酚为底物的最大反应速度为:Vmax=22.452U/min,Km=128.2mmol/L。蜜柚多酚氧化酶作用的最适pH6.4,最适温度为10℃。不同时间的蜜柚多酚氧化酶的平均活性呈逐渐下降的趋势。
The activity of polyphenol oxidase（PPO）in flesh of Miyou pomelo fruits was measured with spectrophotometer at 420nm using catechol as substrate.The effects of the different substrate concentration,temperature,pH,substrate concentration on PPO activity were studied and the reaction kinetic equation was established.The results showed that the optimum temperature and pH were 10℃and pH 6.4,respectively.The reaction kinetic of enzymatic reaction in this experiment was built according to Michaelis equation.The Vmax and Km were 22.452U/min and 128.2mmol/L,respectively.The average activity of PPO at different time decreases continuously.
出处
《北方园艺》
CAS
北大核心
2010年第17期171-174,共4页
Northern Horticulture
基金
科技部"十一五"科技支撑计划重点资助项目(2006BAD3001)
关键词
蜜柚
多酚氧化酶
酶学特性
测定
pomelo
polyphenol oxidase
enzymatic properties
measurement
