Description
Introduction: Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF) or vasculotropin, is a homodimeric 34 -42 kDa, heparin-binding glycoprotein with potent angiogenic, mitogenic and vascular permeability-enhancing activities specific for endothelial cells. The amino acid sequence of VEGF exhibits primary structural, as well as limited amino acid sequence, homology with that of the A and B chains of PDGF. VEGF is expressed by numerous rodent and human tumor cells, including human lung adenocarcinoma, bladder carcinoma, fibrosarcoma, HL60 promyelocytic leukemia, GS-9L glioma, and U937 lymphoma cells. In normal tissues, VEGF expression has been found in activated macrophages, keratinocytes, renal glomerular visceral epithelium and mesangial cells, hepatocytes, smooth muscle cells, Leydig cells,embryonic fibroblasts and bronchial and choroid plexus epithelium. The expression of VEGF is upregulated by phorbol ester, TGF-a and in hypoxia. In the conditioned media of human choriocarcinoma cells (JAR and JE-3), the occurrence of VEGF/PlGF heterodimers has also been observed.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated with an antibody specific to VEGF. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for VEGF 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 VEGF, 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 VEGF in the samples is then determined by comparing the O.D. of the samples to the standard curve