中文摘要：

目的：利用基因工程技术获得与结缔组织生长因子（CTGF）特异性结合的小肽。方法：设计并合成带有肠激酶切割位点的基因片段，插入pET-32（a）^＋质粒载体中硫氧化还原蛋白基因下游，构建重组质粒，转入E．coli BL21表达菌中，用终浓度1mmol·L^-1的IPTG诱导表达融合蛋白；用热变性和硫酸铵分级沉淀对融合蛋白进行初步纯化，然后用亲和层析进一步纯化，经肠激酶切割，最后用凝胶过滤层析分离获得目的小肽；用反相色谱对所获小肽进行纯度鉴定。结果：所构建的重组质粒测序结果与预期一致：诱导表达后用SDS-PAGE鉴定，发现在相对分子质量20000处有浓密的表达条带出现，与预期一致；融合蛋白用热变性和硫酸铵分级沉淀进行初步纯化，得率分别为78、6％和52．3％；用亲和层析纯化得率为50．5％；经肠激酶切割后用凝胶过滤层析分离获得目的小肽，用反相色谱鉴定其纯度大于95％；最终每升发酵液获得3．4mg目的肽。结论：成功制备CT-GF特异性结合肽，为进一步研究该小肽的生物学活性打下基础。

英文摘要：

Objective To obtain the peptide specifically binding to connective tissue growth factor by genetic engineering technique. Methods A gene fragment with enterokinase cleavage site was designed and synthesized by PCR method, and inserted into downstream of fusion partner thioredoxin gene of pET-32（a）^＋ plasmid vector. The recombinant plasmid was constructed and transfered into E. coli BL21 （ DE3 ）. The fusion protein was induced by IPTG up to the final concentration of 1 mmol·L^-1, and was then purified using methods of heat denaturation and fractional precipitation with ammonium sulfate. For further purification, an affinity chromatograph was applied. The interest peptide was finally obtained by gel filtration chromatography （GFC） after fusion protein was digested with enterokinase. The purity of the peptide was identified by reversal-phase chromatography. Results The sequencing result of the recombinant plasmid was consistent with the expectance. There was an expressive band of 20 000 which was consistent with the expected molecular weight by SDS-PAGE analysis. The yields of fusion protein purified by heat denaturation, fractional precipitation with ammonium sulfate and affinity chromatograph were 78.6% , 52.3% and 50.5% respectively. The peptide was finally obtained by GFC after cleavage by enterokinase. The purity identified by reversal-phase chromatography was more then 95%. The peptide of 3.4 milligram per liter broth was detected. Conclusion The peptide specifically binding to connective tissue growth factor was obtained successfully. And it is valuable for the further study of the biologic activity of the peptide.