仙人掌超氧化物歧化酶的制备研究

Research on the Preparation of Superoxide Dismutase from Cactus

对500g仙人掌进行捣碎匀浆、硫酸铵分级沉淀浸提、离心、除杂蛋白、溶解等一系列处理后得到SOD(超氧化物歧化酶)粗酶液。所得粗酶液用聚酰胺(100目)层析柱层析实现纯化,再经过冷冻干燥即得到含有SOD的白色粉末。用联苯三酚法测定该白色粉末具有的酶活力。实验结果显示得到含有SOD的白色粉末酶活力为0.9590×104U/g粉末。影响酶活力大小的外界因素主要包括pH值、温度、抑制剂。结果显示在pH值为7.5～8.5时酶活力最大,稳定性也好。温度维持在25～30℃时酶活力最高。由于过氧化氢和氰化钾能使仙人掌SOD的酶活力显著下降,因而可以判断从仙人掌中提取到的SOD是Cu·Zn-SOD。

After a series of treatment to cactus including crush and pulping, ammonium sulfate precipitation extract, centrifuge, getting rid of protein and fuse, the superoxide dismutase was obtained in the liquid. The liquid containing superoxide dismutase needed to be purified with chromatography. The medium for chromatography was polyamide. The activity of the powder was measured with pyrogallol. The result powder activity was 0.9590 ×10^4U/g. The activity of superoxide dismutase would be affected by the change of temperature, pH and inhibitor. The relationship between the activity of superoxide dismutase and these factors was studied in the experiment. The results showed that when pH was between 7.5 to 8.5, the activity of superoxide dismutase was in a optimum range. Superoxide dismutase activity was sensitive to the change of ambient conditions. The activity would be lost at high temperature. The superoxide dismutase was the most active at the temperature of 25 to 30℃. The activity of superoxide dismutase would decrease obviously under the effect of H2O2 and KCN. It was analysed that the superoxide dismutase in Cactus was Cu · Zn-SOD.