欧洲鳗鲡血清免疫球蛋白纯化及其结构分析

应用亲和层析技术提纯欧洲鳗鲡免疫球蛋白（Ig），并对欧鳗Ig的结构和抗原性进行分析。层析结果表明：Ig蛋白呈现一个锐形曲线，蛋白峰与抗原活性峰高度重叠。SDSPAGE分析表明：欧鳗Ig重链分子量为68 kD，轻链有3条，分子量分别为21 kD、23 kD和26 kD。凝胶电泳结果显示：在非变性非还原条件下，欧鳗Ig有790 kD和350 kD 2条蛋白带，在变性非还原条件下有790 kD、593 kD和350 kD 3条蛋白带。Western-blotting试验证实：兔抗欧鳗Ig能识别欧鳗Ig的多种不同聚合体和Ig的重链，但不能识别Ig的轻链。结论：欧鳗Ig在自然条件下可能以四聚体和二聚体的形式存在，这与其它硬骨鱼的Ig形式有差异。欧鳗Ig链间二硫键不健全,在SDS作用下可解聚产生多种不同分子量的聚合体，首次揭示欧鳗Ig的轻链有3种异型。

Purification and structure analysis of serum immunoglobulin in Anguilla anguilla

The purification of serum immunoglobulin(Ig) of European eel(Anguilla anguilla)was carried out by affinity chromatography.The structure and the antigenicity of eel's serum Ig were analyzed by electrophoresis and Western-blotting.The results showed that after separating by the affinity column,the amount of eluted protein of serum Ig was showed as a sharp curve on plotting paper.And the protein curve was highly correlated with the antigenic activity curve when analyzing the sample by ELISA.SDS-PAGE demonstrated that the heavy chain of the serum Ig was 68 kD in size,there were three light chains with the molecular weight of 21 kD,23 kD and 26 kD respectively.Under non-reduced and non-denatured conditions,the serum Ig appeared as two protein bands with the molecular weight 790 kD and 350 kD,and showed 790 kD,593 kD and 350 kD three protein bands under denatured and non-reduced conditions.Western blotting revealed that the rabbit antiserum could recognize various polymers,heavy chain of the serum Ig,but could not react with the light chains.In combination with the above results,the natural form of the serum Ig could be presented as tetramer and dimer,which was different from other serum Ig of teleost.The disulfide linkage between the heavy chains of the Ig was incomplete.Under the reaction of the SDS the Ig had come apart into various smaller polymers.There were three distinct light chains found in the Ig of European eel for the first time.