| Vascular endothelial growth factor (VEGF or VEGF-A), also known as vascular permeability factor (VPF), is a potent mediator of both angiogenesis and vasculogenesis in the fetus and adult (1-3). It is a member of the PDGF family that is characterized by the presence of eight conserved cysteine residues and a cystine knot structure (4). Humans normally express alternately spliced isoforms of 121, 145, 165, 183, 189, and 206aa in length (4). VEGF165 appears to be the most abundant and potent isoform, followed by VEGF121 and VEGF189 (3, 4). Additionally, an active ~18kD form, VEGF111, can be induced in tumor cells by treatment with genotoxic agents and ultraviolet (UV-B) irradiation (5). Like VEGF121, VEGF111 lacks the basic heparin-binding region encoded by exons 6 and 7, and is freely diffusible (4, 5). VEGF111 also lacks major proteolytic cleavage sites encoded by exon 5, giving it additional stability. Human VEGF111 shares 87% aa sequence identity with corresponding regions of mouse and rat VEGF, 93% with feline, equine and bovine VEGF, and 91%, 95% and 96% with ovine, canine and porcine VEGF, respectively. All VEGF forms bind the single pass receptor tyrosine kinases VEGF R1 (also called Flt-1) and VEGF R2 (Flk-1/KDR) on endothelial cells (4). Although VEGF affinity is highest for binding to VEGF R1, VEGF R2 appears to be the primary mediator of VEGF angiogenic activity (3, 4). VEGF is required during embryogenesis to regulate the proliferation, migration, and survival of endothelial cells (3, 4). In adults, VEGF functions mainly in wound healing and in female during reproductive cycle (3). Pathologically, it is involved in tumor angiogenesis and vascular leakage (6, 7). Source: Recombinant protein corresponding to Ala27-Arg137, with an N-terminal Met & Pro28-Arg137 from human VEGF111, expressed in E. coli. MW: The methionyl form~13kD and a truncated form~12.8kD The recombinant human VEGF 111 migrates as an ~12-13kD protein in SDS-PAGE under reducing conditions. Activity: Measured in a cell proliferation assay using HUVEC human umbilical vein endothelial cells. Conn, G. et al. (1990) Proc. Natl. Acad. Sci. USA 87:1323. The ED50 for this effect is 0.6-3ng/mL Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer. |
