Description
Introduction: Midkine (MK, MDK), or Neurite Growth-promoting Factor 2, is a basic heparin-binding growth factor of low molecular weight, a member of the NEGF family whose founding member is pleiotrophin (NEGF1, 46% homologous with MK). It is a nonglycosylated protein, composed of two domains held by disulfide bridges. It is a developmentally important retinoic acid-responsive gene product strongly induced during mid-gestation, hence the name midkine. Restricted mainly to certain tissues in the normal adult, it is strongly induced during oncogenesis, inflammation and tissue repair. MK is pleiotropic, capable of exerting activities such as cell proliferation, cell migration, angiogenesis and fibrinolysis. A molecular complex containing receptor-type tyrosine phosphatase zeta (PTPzeta), low density lipoprotein receptor-related protein (LRP1), anaplastic leukemia kinase (ALK) and syndecans is considered to be its receptor.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to midkine. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for midkine and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. Then a TMB (3,3',5,5' tetramethyl-benzidine) substrate solution is added to each well. Only those wells that contain midkine, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of 450 nm +/- 2 nm. The concentration of midkine in the samples is then determined by comparing the O.D. of the samples to the standard curve