摘要:采用0.2mol/L磷酸盐缓冲溶液匀浆法从鸡腿菇和白灵菇中提取多酚氧化酶(PPO)，并对该多酚氧化酶的酶学特性进行了研究。实验结果表明，以邻苯二酚为底物，白灵菇中的多酚氧化酶的最适pH值为5.6，最适温度为40℃，Km值为9.36×10-3mol/L，Vmax值为8.11×10-3U/min，100℃热处理1.5min、95℃热处理2.5min或90℃热处理3.5min可完全钝化PPO的活性，10mmol/L的异VC钠能有效抑制PPO的酶活性；鸡腿菇中的多酚氧化酶的最适pH值为4.4，最适温度为35℃，Km值为13.5×10-3mol/L，Vmax值为8.97×10-3U/min，100℃热处理1.5min、95℃热处理3min或90℃热处理4min可完全钝化PPO的活性，10mmol/L的L-半胱氨酸能有效抑制PPO的酶活性。
关键词：白灵菇；鸡腿菇；多酚氧化酶；特性
Abstract:The polyphenol oxidase (PPO) of Pleurotus Nebrodensis and Coprinus comatus were extracted by 0.2 mol/L phosphate buffer and its properties was analysed. Experimental results showed that the Pleurotus Nebrodensis optimal pH and temperature were 5.6 and 40℃ respectively, and the Km value and Vmax value with catechol substrate were 9.36×10-3mol/L and 8.11×10-3 U/min respectively, and the PPO would be inactive in 1.5 min, 2.5 min or 3.5min, when the water tempreture was 100℃, 95℃, 90℃individually. D-Isoascorbic acid was strong inhibitors, and the effective concentration of the inhibitor was 10mmol/L.And that the Coprinus comatus optimal pH and temperature were 4.4 and 35℃ respectively, and the Km value and Vmax value with catechol substrate were 13.5×10-3mol/L and 8.97×10-3U/min respectively, and the PPO would be inactive in 1.5 min, 3 min or 4 min, when the water tempreture was 100℃,95℃,90℃, individually. L-cysteine was strong inhibitors, and the effective concentration of the inhibitor was 10mmol/L.
Keywords: Pleurotus Nebrodensis; Coprinus comatus; PPO ; Property
