Recombinant Human VEGF 121

Vascular endothelial growth factor (VEGF) is a polypeptide growth factor and a member of the plateletderived growth factor family, but it is specific for vascular endothelial cells. VEGF acts as a moderate mitogen for those cell types possessing receptors for binding (e.g. vascular endothelial cells) and is a strong angiogenic factor in vivo. At least two different high-affinity receptors for VEGF have been demonstrated in different vascular endothelial cells (e.g. human umbilical vein endothelial cells or bovine aortic endothelial cells) called FLT-1 (VEGF-R1) and KDR (VEGF-R2). In addition to its action as a mitogen, it is a potent vascular permeability factor in vivo, and VEGF is also a chemoattractant molecule for monocytes and endothelial cells. Five different proteins are generated by differential splicing: VEGF121, VEGF145, VEGF165, VEGF189 and VEGF206. The most abundant form is VEGF165. Whereas VEGF121 and VEGF165 are secretable proteins, VEGF145, VEGF189 and VEGF206 are strongly cellassociated. The isoforms VEGF145, VEGF165 and VEGF189 bind to heparin with high affinity. VEGF is apparently a homo-dimer, but preparation of VEGF show some heterogeneity on SDS gels depending of the secretion of different forms and the varying degrees of glycosylation. All dimeric forms possess similar biological activities but the bioavailability is very different. There is good evidence that heterodimeric molecules between the different isoforms also exist and that different cells and tissues express different VEGF isoforms. A related protein of VEGF is placenta growth factor (PlGF) with about 53% homology and VEGF-B with similar biological activities. More recent members of this family are VEGF-C and VEGF-D and virus-derived VEGF-E.