链球菌G蛋白的IgG结合域能够特异性地结合IgG 的Fc区，是制备免疫微阵列的一种理想的IgG固定材料。克隆表达了具有IgG结合活性的3种IgG结合域的GST融合蛋白（GST-GBx），该3种蛋白分别含有1个、2个和3个IgG结合域。采用ELISA对三蛋白IgG结合能力进行了比较分析。结果表明在含B-Domain的量相同的情况下，GST-GB3蛋白固定IgG的量最多，其次为GST-GB2，GST-GB1最弱；对IgG的灵敏度也是GST-GB3最强，GST-GB1最弱，提示GST-GB3固定IgG的能力较其他两蛋白具有明显优势。

The IgG binding domain of Streptococcal Protein G which can selectively immobilizes the Fc regions of immunoglobulin G (IgG) is a kind of good material for oriented immobilization of antibodies in antibody microarrays. Here, genetically engineered three glutathione S-transferase (GST)　fused proteins ,bearing one, two and three B-Domains respectively(GST-GBx). The IgG-bindding ability of GST-GBx was investigated by ELISA. The date revealed that when the B-domain’s quantity of GST-GBx is identical, the GST-GB3 is the most efficient protein among three GST-GBx protein both the capacity and sensibility of binding IgG. The GST-GB2 is the next one and GST-GB1 is the least one. Thus,the GST-GB3 has significantly predominance in comparison to GST-GB2 and GST-GB1.