中文摘要：

超氧化物歧化酶（SOD）家族是保护细胞免受正常代谢过程中产生的活性氧（ROS）毒性所必需的,含Mn2＋离子的超氧化物歧化酶（Mn-SOD,SOD2）是其中最重要的一种。本研究合成了人源SOD2全基因序列,并将其插入带有GST的原核表达载体p GEX-4T-1中,成功构建了GST-SOD2融合蛋白表达质粒。然后,将重组质粒p GEX-4T-1-SOD2转化大肠杆菌BL21（DE3）,用IPTG在25℃下诱导表达融合蛋白,得到可溶性GST-SOD2融合蛋白,经GST亲和树脂纯化得到比活为1 788 U/mg的纯蛋白,分子量约为46 k Da。利用凝血酶切去GST标签后经肝素亲和柱纯化得到了电泳纯的SOD2重组蛋白,该蛋白分子量约为25 k Da,与SOD2全长序列的理论分子量相符,比活为2 000 U/mg。两种重组SOD2蛋白在生理条件下都具有良好的SOD活性,且都具有显著的跨膜能力（P〈0.05）。这些工作为深入研究两种全长重组SOD2蛋白的结构与生物效应建立了基础。

英文摘要：

Superoxide dismutase （SOD） family is necessary to protect cells from the toxicity of reactive oxygen species produced during normal metabolism. Among SODs, manganese-containing superoxide dismutase （Mn-SOD, SOD2） is the most important one. The DNA fragment containing the full nucleotide of full-length human SOD2 was synthesized and inserted into the prokaryotic expression vector pGEX-4T-1 with tag GST. DNA construct was then transformed into Escherichia coli BL21 （DE3） and expression was induced with IPTG at 25 ~C. The recombinant fusion protein GST-SOD2 （46 kDa） was purified from the bacterial lysate by GST resin column affinity chromatography. GST tag was cleaved with thrombin, and a crude SOD2 recombinant protein （25 kDa） was obtained and further purified by heparin affinity chromatography. Activities of the two SOD2 proteins were 1 788 and 2 000 U/mg, respectively. Both SOD2 proteins were stable under physiological condition and cell-penetrating （P〈0.05）. Our findings open the possibility to study the structure and effects of two full-length recombinant SOD2 proteins.