Abstract: In this paper，superoxide dismutase (SOD) was used as a template，and purification and modification were coupled to obtain more stable modified SOD with higher activity. SOD was mixed with DEAE-52 and Cu2+ chelating-sephadex G-75 without being washed immediately but modified by activated PEG5000 upon that solid-phase column，then washed specifically. The modification and purification of SOD were completed at the same time. Finally，the specific activity of PEG-SOD after IEC-modification was 9638.0 U/mg，with a purification factor of 1.87. It was modified at 35.3% of its free amino groups. And the specific activity of PEG-SOD after MCAC-modification was 9067.8 U/mg，with a purification factor of 1.755. It was modified at 40.9% of its free amino groups，retained 87.1% of enzymatic activity of native SOD. It is feasible to couple the purification and modification of SOD.And the coupling of MCAC and modification was better than this of IEC and modification.

摘要： 以超氧化物歧化酶（superoxide dismutase，SOD）为模板蛋白，将其分离纯化过程和修饰过程耦合起来，从而获得比活更高、稳定性更好的修饰SOD。将SOD选择性地吸附在DEAE-52层析柱和铜离子螯合葡聚糖凝胶柱上，先不经洗脱分离，直接用活化的聚乙二醇（PEG）5000对吸附在柱上的SOD进行化学修饰，再通过特异性洗脱分离获得PEG-SOD，使SOD分离纯化和修饰过程同步完成。SOD通过离子交换吸附层析-PEG修饰耦合过程和金属螯合层析－PEG修饰耦合过程，所得的PEG-SOD比活力分别为9638.0 U/mg和9067.8 U/mg，纯化倍数分别为1.87倍和1.755倍，氨基修饰率分别为35.3%和40.9%。结果表明SOD的分离纯化-化学修饰耦合过程是可行的，且金属螯合层析-修饰耦合过程的效果要优于离子交换吸附层析-修饰耦合过程。