ELISA法定量测定人血清、血浆、细胞培养物上清或其它相关液体中Midkine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Midkine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Midkine抗原、生物素化的抗人Midkine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Midkine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 human Midkine concentrations in cell culture supernates, serum, and plasma.

 

Midkine (MK, also called neurite growth promoting factor 2, NEGF-2), a product of a retinoic acid responsive gene, is a secreted 13 kDa protein belonging to the family of heparin binding growth/differentiation factors. MK shares 45% sequence identity with other member of this family  called Pleiotrophin (HB-GAM). Midkine is composed of two domains held together by disulfide linkages. The C-terminally located domain contains two heparin binding sites and is usually responsible for midkine activity. Part of the MK activity is enhanced by dimerization of MK.  Midkine has been found in vertebrates from human to zebrafish and is most strongly expresed in midgestation. In the adult MK expression is restricted. In addition to normal development, MK is also involved in the pathogenesis of diseases e.g. inflammatory diseases, human carcinomas such as esophageal, stomach, colon, pancreatic, thyroid, lung, urinary, hepatocellular, neuroblastoma, glioblastoma, Wilm′s tumor etc. High MK levels are associated with poor prognosis in some type of cancer. The  increased expresion in many carcinomas indicates that  MK can be applied to the diagnosis of malignancy. Midkine is expressed during the reparative stage of bone fractures, also supresses infection of certain viruses including HIV in target cells. Anti-apoptotic and cell protecting activity of midkine makes it to be a promissing in therapy.

 

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal

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