分光光度法对马铃薯中酪氨酸酶活性的测定

[目的]研究酪氨酸酶的活性，为防止马铃薯及其他舍酪氨酸酶的水果和蔬菜等发生褐变提供参考。[方法]以马铃薯为原料，利用分光光度法测定酪氨酸酶的活性；为确定提取酪氨酸酶的适宜条件，测定不同温度和不同pH值对酶活性影响。[结果]结果显示，多巴溶液的吸收光谱最大吸收峰λmax为480nm，随着时间的增大吸光度变化趋于稳定。以此建立动力学曲线，由曲线的斜率可计算出酪氨酸酶的活性，并由试验得出酪氨酸酶的活性受温度和溶液的pH值影响较大。因此，提取和测定酪氨酸酶的活性时的适宜条件为：可见波长λmax为480nm，温度控制在30℃，pH值6．5。[结论]为保障酪氨酸酶的活性，在提取和测定时应选择适宜的条件。

Determination of the Tyrosinase Activity in Potato with Spectrophotometric Method

[Objective] The reference for the prevention of the browning of the potato and other fruits/vegetables containing tyrosinase was provide through the study on the activity of tyrosinase.[Method] The potato being taken as experimental raw material, the activity of tyrosinase in it was determined with the spectrophotometric method and the effect of different temperatures and different pH values on the activity of tyrosinase was experimented in order to ensure the appropriate extraction condition of tyrosinase.[Results] The results of l showed that the maximum absorption peak of the Dopa solution to spectra was 480 nm and its change gradually stabilized with the time-increasing.Based on that a kinetic curve could be established and the activity of tyrosinase could be calculated through the slope of the curve.The experimental result also indicated the impact of the temperature and l of pH value of solution on the activity of tyrosinase was great.Therefore, the appropriate conditions of the extraction and determination of the activity of tyrosinase was the visible wavelength max, 480 nm; the temperature, 30 ℃; and the pH value, 6.5.[Conclusion] In order to protect the activity of tyrosinase, the suitable condition extraction and determination of the activity of tyrosinase should be chosen in actual operation.