研究了色谱方法对伴大豆球蛋白组成3个亚基的分离纯化工艺条件,并利用圆二色光谱对纯化得到的3个亚基的二级结构和三级结构进行了表征。结果显示:利用离子交换色谱(DEAE-sepharose fast flow,DEAE为二乙氨乙基)和金属螯合层析(Immobilized metal affinity column,IMAC)相结合的方法,能将3个亚基组分完全分开,得到了能制备相对大量的3个亚基α′,α和β的稳定工艺,纯度为95%,回收率达75%。远紫外CD结果显示,在3个亚基的二级结构中,α螺旋较少,但都具有较高含量的β折叠和无规卷曲;近紫外CD结果显示,3个亚基在制备过程中因为尿素的变性作用,都已经散失了三级结构。
The isolation process of the three constituent subunits of soybean conglycinin was studied by the chromatographic method and then the secondary and tertiary structures of three constituent subunits were characterized. The results showed that the combination of diethylaminoethyl (DEAE)-Sepharose Fast Flow column and immobilized metal affinity column (IMAC) succeeded in isolating these subunits completely, giving high purity (95%) and a total recovery ratio of 75%. The data from far-UV CD showed the subunits had relatively low content of α-helix and high content of β-sheet, β-turn and unordered structure. The contents of their β-sheet in the isolated subunits were higher than those of conglycinin, whereas their contents of unordered structures were lower than conglycinin. The near-UV CD showed the isolated subunits lost their tertiary structure due to the denaturalization of urea in the purification process.