中文摘要：

目的：筛选和鉴定肿瘤血管靶向肽GX1（CGNSNPKSC）的结合受体。方法：化学合成生物素标记的GX1，培养内皮细胞并收集细胞膜蛋白；利用免疫沉淀的方法进行免疫磁珠分离，富集能与血管特异性短肽GX1结合的蛋白质；利用生物素-亲和素系统进行westernblot免疫检测，筛选出能和GX1结合的目的条带；利用液相色谱-二级质谱（LC—MS／MS）对能与血管特异性短肽GX1结合的蛋白质进行测序鉴定。结果：利用免疫沉淀和westernblot的方法，获得了能与GX1结合的蛋白条带，其分子量为13KDa。利用LC-MS／MS及生物信息学分析，获得了8个候选蛋白：cDNA FLJ40018fis，clone STOMA 2006398，cytochromeP45019A1，pmble histone—lysine N-methyltransferaseASHlL，adenylylcyclase—associated protein2（CAP2），similar to ankyrin repeat domain20A，diacylglycerol kinaseiota（DGKI），isoform 2 of Inositol1，4，5-trisphosphate receptor type1，similartoannexinA2 isoforml。结论：利用免疫沉淀-质谱法获得了8个GX1结合受体的候选蛋白，为进一步寻找血管抑制治疗的靶标奠定了一定的实验基础。

英文摘要：

Objective ：To screen and identify the receptors of GX1 （CGNSNPKSC） peptide binding to tumor vascular endothelium. Methods： We synthesized the biotin -labeled GX1 peptide and collected the membrane proteins of the cultured endothelial cells. By using immunoprecipitation and immune magnetic beads separation, we obtained proteins combined with GX1 peptide. By using biotin - avidin system and western blot, the protein band that specif- ically bound to GX1 peptide was screened. Then, the protein band was identified by tandem mass spectrometry （LC - MS/MS）, and analyzed with bioinformatics. Results： By using immunoprecipitation and western blot, one band in the position of 13KDa was found to bind selectively to the GX1 peptide. Using tandem mass spectrometry analysis and bioinformatics analysis, 8 candidate proteins was obtained, including cDNA FLJ40018fis, clone STOMA2006398, cytochromeP450 19A1, probable histonelysine N- methyltran feraseASH1L, adenylyl cyclaseassociated protein 2 （ CAP2）, similar to ankyrin repeat domain 20A, diacylglycerol kinase iota （ DGKI ）, isoform2 of Inositol 1,4,5 - trisphosphate receptor type 1, and similar to annexinA2 isoforml. Conclusion： By using immunoprecipitation and mass spectrometry, 8 candidate proteins were identified, which may provide some experimental basis for probing into new targets of anti - vascular therapy.