预期应用
ELISA法定量测定人血清、血浆或其它相关液体中纤维连接蛋白(FN)含量。
介绍
纤维粘连蛋白属非胶原糖蛋白的一种, 称为冷不溶球蛋白,广泛存在于动物界, 包括海绵、海胆及哺乳动物类。在脊椎动物中, 纤粘连蛋白以可溶的形式存在于血浆和各种体液中,称为血浆纤维粘连蛋白；以不溶的纤维存在于细胞外基质、细胞之间及某些细胞表面, 称为细胞纤粘连蛋白。FN是高分子量的粘附性的糖蛋白, 含糖约5%。FN由两个亚基组成的二聚体，每个亚基的相对分子质量约250kDa, 各亚基在C末端形成两个二硫键交联。
实验原理
本试剂盒应用双抗体夹心酶标免疫分析法测定标本中纤维连接蛋白水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入纤维连接蛋白抗原、生物素化的抗人纤维连接蛋白抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的纤维连接蛋白呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。
Intended use
This immunoassay kit allows for the specific measurement of Human Fibronectin concentrations in cell culture supernates, serum and plasma.
Introduction
Fibronectin (Fn) is a large modular glycoprotein that is found as a polymeric fibrillar network in the extracellular matirx (ECM) and as soluble disulfide-linked dimeric protomers in plasma and other body fluids. The protein subunit is made up of three types of homologous structural repeats termed Fn type I, type II, and type III repeats. Multiple isoforms of the protein formed by alternative splicing at numerous sites, resulting in insertions of extra type III domains (EDA and ECB) or parts of the variable type III connecting segment (V/IIICS), have been identified. Fibronectin is a ligand for fibrin, heparin, chondroitin sulfate, collagen/gelatin, and many integrin receptors. It is involved in multiple cellular processes including cell adhesion/migration, blood clotting, morphogenesis, tissue repair, and cell signaling. Fibronectin functions are mediated by the insoluble polymeric fibrils in the ECM.
Conversion of the non-functional soluble fibronectin to fibronectin fibrils in the ECM is tightly regulated. The process is initiated by binding of fibronectin to cell surface integrins, resulting in conformational changes and exposure of cryptic epitopes necessary for polymerization.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for Fibronectin has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Fibronectin present is bound by the immobilized antibody. An enzyme-linked polyclonal antibody specific for Fibronectin is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of Fibronectin bound in the initial step. The color development is stopped and the intensity of the color is measured.
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