蕨菜多酚氧化酶的性质

Characteristics of polyphenol oxidase in pteridium aquilinum

以冷冻丙酮制备蕨菜多酚氧化酶丙酮粉,用分光光度法研究pH、温度、底物浓度,抑制剂对酶活性的影响,结果表明,以邻苯二酚为底物,该酶的最适pH值为7 4 ,最适温度为2 5℃;Km为39 .86mmol/L ,Vm为0 .6 86OD/min ,90℃热处理5 0s可钝化PPO的活性;抗坏血酸、亚硫酸钠为强烈抑制剂,175mg/L的亚硫酸钠、2 2 5mg/L的抗坏血酸能有效抑制PPO的活性。

Acetone powder of PPO in pteridium aquilinum was extracted from ice-cold acetone, effects of pH, temperature, concentration of substrate, and inhibitors on PPO's activity were investigated by using the spectrophotometric method. Experimental results showed that the optimal pH and temperature were 7.4and 25 ℃,Km and Vm of PPO with catechol substrate were 39.86 mmol/L and 0.686 OD/min respectively, the extincting condition of PPO was 50 s at 90 ℃,Sodium sulfite and Ascorbic acid were strong inhibitors, the effective concentrations of inhibitor were 175 mg/L and 225 mg/L respectively.