ELISA法定量测定大鼠血清、血浆、尿液或其它相关液体中NGAL含量。

本试剂盒应用双抗体夹心酶标免疫分析法测定标本中NGAL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NGAL抗原、生物素化的抗大鼠NGAL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NGAL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。

This immunoassay kit allows for the specific measurement of rat NAGL concentrations in urine, serum, and plasma.

 

NGAL (neutrophil gelatinase-associated lipocalin) belongs to the lipocalin family of proteins. These are typically small secreted proteins characterized by their ability to bind small, hydrophobic molecules in a structurally conserved pocket formed by β-pleated sheet, to bind to specific cell-surface receptors and to form macromolecular complexes. NGAL has many synonyms: it also known as NL (neutrophil  lipocalin; HNL: rat NL), lipocalin, oncogene protein 24p3 or uterocalin (in the mouse) and neu-related lipocalin or 25 kDa α2-microglobulin-related protein6 (in the rat). Rat NGAL consists of a single disulfide-bridged polypeptide chain of 178 amino-acid residues with a calculated molecular mass of 22 kDa, but glycosylation increases its apparent molecular mass to 25 kDa. In neutrophils (neutrophilic polymorphonuclear leukocytes) and urine it occurs as monomer, with a small percentage of dimer and trimer, and also in complex with 92-kDa rat neutrophil type IV collagenase, also called gelatinase B or matrix metalloproteinase-9 (MMP-9). NGAL was originally isolated from the supernatant of activated rat neutrophils,  but it is also expressed at a low level in other rat tissues including the kidney, prostate and epithelia of the respiratory and alimentary tracts. It is strongly expressed in adenomas and inflamed epithelia of the bowel,  adenocarcinomas of the breast, and urothelial carcinomas. Because of its small molecular size and resistance to degradation, NGAL is readily excreted and detected in the urine, both in its free form and in complex with MMP-9. Urinary levels correlate with plasma or serum levels whatever the cause of increased NGAL production (AntibodyShop data), but particularly high urinary levels can be expected when it is released directly into the urine by the kidney tubules or urothelial carcinomas. It is uncertain how far NGALMMP-9 complexes from sources remote from the urinary tract are excreted as such into the urine or reform in the urine after independent excretion of NGAL and MMP-9.

 

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for NAGL has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any NAGL present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for NAGL 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 NAGL bound in the initial step. The color development is stopped and the intensity of the color is measured.