Description
Introduction: The thrombospondins (TSP) are a family of multifunctional proteins. The family consists of thrombospondins 1-5 and can be divided into 2 subgroups: A, which contains TSP-1 and -2, and B, which contains TSP-3, -4 and -5 (also designated cartilage oligomeric protein or COMP). TSP-1 and -2 are homotrimers, consisting of three identical subunits, whereas TSP-3, -4 and -5 are homopentamers. TSP-1 is a multi-domain matrix glycoprotein that has been shown to be a natural inhibitor of neovascularization and tumorigenesis in healthy tissue. It interacts with at least 12 cell adhesion receptors, including CD36, alphav integrins, beta1 integrins, syndecan, and integrin-associated protein (IAP or CD47). It also interacts with numerous proteases involved in angiogenesis, including plasminogen, urokinase, matrix metalloproteinase, thrombin, cathepsin, and elastase.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to TSP-1. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for TSP-1 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 TSP-1, 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 TSP-1 in the samples is then determined by comparing the O.D. of the samples to the standard curve