人源EC-SOD在毕赤酵母中的构建与表达
Construction of extracellular superoxide dismutase and expression in Pichia pastoris

利用基因工程技术构建表达载体并电转化至毕赤酵母中，成功实现人源EC-SOD在毕赤酵母X33中的表达. 重组蛋白经盐酸羟胺法测得25mL摇瓶发酵液上清酶活为508U·mg-1，5L发酵液上清酶活为909U·mg-1. 发酵液上清用硫酸铵沉降后，使用DEAE弱阴离子交换树脂初步分离纯化出较纯的EC-SOD，测得比活为1700U·mg-1，并进行氯化硝基四氮唑蓝（NBT）活性定性染色. 结果表明，毕赤酵母成功胞外表达具有一定活性的SOD蛋白.
A highly expression strain was constructed by genetic engineering technology. Furthermore，EC-SOD derived from Pichia showed a high activity. EC-SOD was exported into the 25mL culture medium with an antioxidative activity of 508U·mg-1；5L culture medium with an antioxidative activity of 909U·mg-1. The supernatant was concentrated and purified by DEAE rsin. And the purified EC-SOD show the antioxidative activity of 1700U·mg-1. Finally the recombined protein show the activity of enzyme has been identified through NBT analysis