A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure,which comprised phosphate buffer extraction,ammonium sulphate precipitation,ion exchange chromatography on Q-sepharose colu...A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure,which comprised phosphate buffer extraction,ammonium sulphate precipitation,ion exchange chromatography on Q-sepharose column,and gel filtration chromatography on Superdex 200 10/300GL.The E.linza superoxide dismutase(ElSOD) was purified 103.6-fold,and a yield of 19.1%and a specific activity of 1 750 U/mg protein were obtained.The SDS-PAGE exhibited ElSOD a single band near 23 kDa and the gel filtration study showed ElSOD’s molecular weight is near 46 kDa in nondenatured condition,indicating it’s a homodimeric protein.ElSOD is an iron-cofactored superoxide dismutase(Fe-SOD) because it was inhibited by hydrogen peroxide,insensitive to potassium cyanide.The optimal temperature for its maximal enzyme activity was 35°C,and it still had 29.8%relative activity at 0°C,then ElSOD can be classified as a cold-adapted enzyme.ElSOD was stable when temperature was below 40°C or the pH was within the range of 5–10.The first 11 N-terminal amino acids of ElSOD were ALELKAPPYEL,comparison of its N-terminal sequence with other Fe-SOD N-terminal sequences at the same position suggests it is possibly a chloroplastic Fe-SOD.展开更多
基金Supported by the National Key Technology R&D Program of China(No.2012BAC07B03)
文摘A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure,which comprised phosphate buffer extraction,ammonium sulphate precipitation,ion exchange chromatography on Q-sepharose column,and gel filtration chromatography on Superdex 200 10/300GL.The E.linza superoxide dismutase(ElSOD) was purified 103.6-fold,and a yield of 19.1%and a specific activity of 1 750 U/mg protein were obtained.The SDS-PAGE exhibited ElSOD a single band near 23 kDa and the gel filtration study showed ElSOD’s molecular weight is near 46 kDa in nondenatured condition,indicating it’s a homodimeric protein.ElSOD is an iron-cofactored superoxide dismutase(Fe-SOD) because it was inhibited by hydrogen peroxide,insensitive to potassium cyanide.The optimal temperature for its maximal enzyme activity was 35°C,and it still had 29.8%relative activity at 0°C,then ElSOD can be classified as a cold-adapted enzyme.ElSOD was stable when temperature was below 40°C or the pH was within the range of 5–10.The first 11 N-terminal amino acids of ElSOD were ALELKAPPYEL,comparison of its N-terminal sequence with other Fe-SOD N-terminal sequences at the same position suggests it is possibly a chloroplastic Fe-SOD.
