以邻苯二酚为底物 ,采用分光光度法在 4 0 5 nm波长测定小麦全籽粒浸提液的吸光度变化 ,以此反映小麦多酚氧化酶活性的大小。从反应开始到 5 min时间段酶促反应最快 ,品种间差异较大 ,随后则逐渐下降 ;浸泡时间对全籽粒浸提法测定多酚氧化酶活性具有显著影响。浸泡时间小于 2 0 h,品种间差异较小 ;浸泡时间超过 30 h,酶液自身吸光值增加较多 ,因此浸泡时间以 2 5～ 30 h为宜。小麦多酚氧化酶与底物反应较适宜的温度和 p H为 35℃和6 .0左右 Using catechol as substrate, spectrophotometry was used to measure the change of absorbance of wheat whole grain extract at the wavelength of 405 nm to reflect the activity of wheat polyphenol oxidase. From the start of the reaction to 5 min, the enzymatic reaction was the fastest, and the difference between the two cultivars was large, then decreased gradually. The soaking time had a significant effect on the determination of polyphenol oxidase activity by whole grain extraction. Soaking time is less than 20 h, the difference between varieties is small; Soaking time more than 30 h, enzyme absorbance increased more self-so the soaking time to 25 ~ 30 h is appropriate. Wheat polyphenol oxidase and substrate reaction temperature and p H is 35 ℃ and about 6.0