可溶性人源含硒抗体酶GPx的研究

Studies of Soluble Human Catalytic Antibody with Glutathione Peroxidase Activity

对噬菌体展示人单链抗体库进行筛选 ,得到与半抗原 S-二硝基苯取代的谷胱甘肽二丁酯特异结合的单链抗体 3B1 0 .用计算机模拟分析了单链抗体的空间结构 ,发现抗原结合的 CDR3区位于抗体的表面 ,推测其可能进一步参加硒化反应 .利用突变引物 ,在大肠杆菌中表达了可溶性抗体蛋白 ,并用化学方法将催化必需基团硒代半胱氨酸 ( Sec)组装到 3B1 0抗原结合部位 ,获得了具有谷胱甘肽过氧化物酶活力的人源抗体酶 .动力学研究结果表明 ,抗体酶和天然酶一样 。

By screening the phage\|displayed human single chain antibody library, we have got the specific single chain antibody bound to GSH\|S\|DNP butyl ester as the hapten. The tertiary structure of the protein was analyzed with the aid of computer, and the results showed the CDR3 region located on the surface of the antibody. The soluble antibody was expressed in \%E.coli\%. and the active site serine was converted into selenocysteine with the chemical modifying method, which resulted in the catalytic antibody with GPx activity of 80 U/μmol. Furthermore, the same Ping\|Pong mechanism as the natural GPx was observed when the kinetic behavior of the antibody was studied.