【摘要】 采用分光光度法,研究了李多酚氧化酶(PPO)的特性,包括不同温度、pH值、底物浓度和抑制剂对PPO活性的影响,以及PPO的热稳定性。结果表明:李PPO的最适酶促反应温度为30℃;最适pH值为5.5;Km为123mmol/L;Vm为0.522■OD/min;90℃热处理2min可钝化PPO的活性;抗坏血酸和亚硫酸钠为强抑制剂,质量分数为189mg/kg的亚硫酸钠和317mg/kg的抗坏血酸能有效抑制PPO的活性。更多还原

【Abstract】 The Characteristics of polyphenoloxidase of plum were studied in this paper by spectrophotometry,including the effects of different temperature,pH,concentration of substrate and inhibitors on PPO activity,as well as stability to heat.The results showed that the optimum temperature of PPO was 30 ℃ and the optimum pH was 5.5.Km value and Vm value of PPO were 123 mmol/L and 0.522■OD/min respectively.The extinct condition of PPO was 2 minutes at 90 ℃.Ascorbic acid and sodium sulfite were strong inhibitors,with the effective concentration being 317 mg/kg and 189 mg/kg respectively.更多还原