本试剂盒应用双抗体夹心酶标免疫分析法测定标本中EL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EL抗原、生物素化的抗大鼠EL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EL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 rat EL concentrations in cell culture supernates of smooth muscle cells, serum, and plasma.
Introduction
Endothelial lipase (EL) was initially cloned by both of these laboratories using entirely different strategies. Endothelial lipase was identified as a transcript that was upregulated in cultured rat umbilical vein endothelial cells undergoing tube formation, whereas the Rader group cloned endothelial lipase as a transcript that was upregulated in the rat macrophage-like cell line THP-1 exposed to oxidized LDL. Database searches revealed that endothelial lipase shows strong sequence similarity to lipoprotein lipase (44 percent identity) and hepatic lipase (41 percent identity), two well-characterized lipases that function at vascular endothelial surfaces. Critical motifs associated with lipase activity (GXSXG and the catalytic triad S169, D193, H274), and with heparin binding were strongly conserved. Interestingly, in contrast to both lipoprotein lipase and hepatic lipase, endothelial lipase has little triglyceride hydrolase activity in vitro but instead cleaves fatty acids from the sn-1 position of phosphatidylcho-line. In in vitro assays the enzyme is most active on lipids presented in HDL, although it will release fatty acids from all classes of lipoproteins. Consistent with this finding, adenovirus-mediated overexpression of endothelial lipase in LDL receptor-deficient mice reduced plasma concentrations of VLDL and LDL cholesterol by about 50 percent, whereas HDL-C decreased to almost zero in these animals. These data suggested that endothelial lipase may play a role in HDL catabolism.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal
antibody specific for EL has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any EL present is bound by the immobilized antibody. An
enzyme-linked monoclonal antibody specific for EL 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 EL bound in the initial step. The color
development is stopped and the intensity of the color is measured.
