本试剂盒应用双抗体夹心酶标免疫分析法测定标本中DPPⅣ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DPPⅣ抗原、生物素化的抗大鼠DPPⅣ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DPPⅣ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 DPPⅣ concentrations in cell culture supernates, serum, and plasma.
Introduction
Dipeptidyl Peptidase IV (DPPIV), also known as T-cell activation antigen CD26 and adenosine deaminase (ADA) complexing protein 2, is a serine protease that releases Xaa-Pro dipeptides from the N-terminus of oligo- and polypeptides. It is a type II membrane protein consisting of a small cytoplasmic tail, a transmembrane region, and a large extracellular domain. The extracellular domain contains glycosylation sites, a cysteine-rich region, and the catalytic active site. In the native state, DPPIV/CD26 is present as a non-covalently linked homodimer on the surface of a variety of cell types.
DPPIV/CD26 plays an important role in many physiological and pathological processes. It interacts with ADA and CD45, providing a co-stimulating signal to the CD3/T-cell receptor complex. It cleaves many chemokines with Xaa-Pro at their N-terminus, altering their receptor specificity and biological function. It degrades many peptide hormones, such as glucagon-like peptide-1, shorting their bioactivity. DPPIV inhibitors are being developed to extend their bioactivity and currently being tested in late-stage clinical trials for the treatment of type 2 diabetes. DPPIV truncates the N-terminus of procalcitonin, a marker for systemic bacterial and fungal infections. DPPIV/CD26 interacts with HIV-1 Tat protein and its binding to ADA is inhibited by HIV envelop protein gp120.
Test principle
This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for DPPⅣ has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any DPPⅣ present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for DPPⅣ 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 DPPⅣ bound in the initial step. The color development is stopped and the intensity of the color is measured.
