与麦芽糖结合蛋白构象有关的单克隆抗体的制备

利用麦芽糖结合蛋白（ＭＢＰ）在大肠杆菌中的高效表达，分别采用亲和层析和变性复性，疑胶过滤的方法纯化了可溶性和包涵体部分的ＭＢＰ。将得到的这两种构象不同的ＭＢＰ分别免疫小鼠并进一步筛选和克隆，各得到５株单克隆抗体株。经制备腹水获得抗体后，地其和构象不同的麦芽糖结合蛋白的结合能力的测定，发现由包涵体部分的ＭＢＰ轩和筛选得到的单克隆抗体中有两对变性蛋白具有更高的结合能力。

The Transferrins from Amphioxus and the Molecular Evolution of Transferrin

An amphioxus transferrin was isolated and purified from the Xiamen amphioxus. Its physio chemical properties are the same as those of Qingdao amphioxus transferrin. It is a glyco protein with a molecular weight of 26 kD that is about a quarter of that of the transferrin from vertebrates. Its partial amino acid sequence and its C terminal fragment were determined. By comparison with the sequence of human serum transferrin, it has been found that the sequence of human serum transferrin can be divided into 4 fragments with about equal size as the sequences of the amphioxus transferrin. There is quite a high homology between the sequences of amphioxus transferrin and each of the 4 fragment as well as between the four fragments. The results demonstrate that the current transferrin may be evolved from an ancestor transferrin with one quarter of the molecular weight as a result of twice gene duplication. Amphioxus transferrin may be the representative from of such ancestor transferrin.