预期应用
ELISA法定量测定人血浆或其它相关液体中内皮素含量。
概述
内皮素是一种由21个氨基酸组成的活性多肽，为目前已知缩血管活性最强的物质。在生理状态下，由于内皮细胞合成内皮素很少且清除速度快，故血浆中内皮素浓度很低。 但在内皮细胞损伤、组织缺血缺氧等情况下，内皮细胞大量合成内皮素并释放入血，成为参与疾病病理生理过程的重要体液因素。
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内皮素水平。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内皮素、生物素化的抗人内皮素抗体、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内皮素呈正相关。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 ET-1 concentrations in plasma.
Introduction
Endothelin-1 (ET-1), a peptide of 21 amino acid residues, is the most potent vasoconstrictive substance known. Originally isolated from porcine aortic endothelial cells, ET-1 is now known to be one of a family of three mammalian vasoactive peptides that also includes Endothelin-2 (ET-2) and Endothelin-3 (ET-3). These related peptides differ from ET-1 at two and six amino acid residue positions, respectively. A fourth peptide, vasoactive intestinal contractor (VIC), is sometimes classified as human ET-2. All members of the endothelin family contain two essential disulfide bridges and six conserved amino acid residues at the C-terminus. Additionally, all of the endothelin family members are synthesized initially as prepropolypeptides of approximately 200 amino acid residues encoded by separate genes. These are proteolytically cleaved to produce biologically-inactive propolypeptides of approximately 40 amino acid residues termed “big endothelins”. Big ET-1 is cleaved by the proteolytic action of a membrane-bound metalloprotease [endothelin-converting enzyme (ECE-1) producing the 21 amino acid residue active peptide.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for ET-1 has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any ET-1 present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for ET-1 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 ET-1 bound in the initial step. The color development is stopped and the intensity of the color is measured.
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