玉米SOD的分离纯化与部分性质研究

Purification and characterization of SOD from maize

目的 建立1种高效而简单的玉米SOD分离纯化方法.方法 采用初步提取、40%～80%硫酸铵分级沉淀、Cu^2＋螯合亲和色谱和DEAE-纤维素离子交换色谱处理的方法从玉米中提取SOD.结果 获得了比活为1.18×10^4U/mg的SOD-A组分,活力回收率为11.7%;纯化后的SOD-A组分经PAGE和SDS-PAGE均为一条带;等电聚焦结果表明该组分的等电点为7.2;经鉴定,该组分属于Cu/Zn-SOD.稳定性研究表明,该组分对热、酸碱及常见变性剂（如尿素）的稳定性较好.结论 利用Cu^2＋螯合亲和色谱和DEAE-纤维素离子交换色谱相结合的方法可以纯化得到高比活、稳定性好的玉米SOD-A组分.

Purpose To construct a simple and efficient way to purify SOD from maize. Methods The methods of preliminary extraction, 40 %-80 % ammonium sulfate fractionation, Cu^2 ＋ chelate affinity chromatography and DEAE-cellulose chromatography to purify SOD-A from maize were used. Results 11.7 % yield of enzyme with specific activity of 1.18 ×10^4 U/（mg· prot） was gained. The purified SOD-A component showed one band on the patterns of both PAGE and SDS-PAGE, the pI was 7.2 by isoelectric focusing and the type was identified Cu/Zn-SOD. The stability study showed that SOD-A component had good stability to temperature, pH and denaturants （such as urea）. Conclusion The SOD-A with high specific activity can be obtained by Cu^2 ＋ chelate affinity chromatography and DEAE-cellulose chromatography, and it had high stability.