VEGFR1, Human, Recombinant, S. frugiperda

Recombinant, human VEGFR-1 expressed in S. frugiperda insect cells. The disulfide linked dimeric recombinant protein contains two polypeptides of 905 amino acids long with a predicted monomeric molecular mass of ~100 kDa. As a result of glycosylation, the monomer migrates as a ~123 kDa protein in SDS-PAGE. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is a secreted heparin binding cytokine expressed in tumor and animal cells. VEGF has been implicated in the control of angiogenesis due to its selective mitogenic stimulation of vascular endothelial cells and enhancement of vascular permeability. VEGF is a ~34-50 kDa dimer of two identical disulfide-linked subunits existing in four molecular species; 121, 165, 189, and 206 amino acid residues long, arising from alternative splicing of a single gene. VEGF binds to two receptor tyrosine kinases, Flt-1 (VEGFR1) and KDR/Flk-1 (VEGFR2) found almost exclusively on human endothelial cells. Flt-1 binds VEGF and a new VEGF-related ligand, placenta growth factor (PIGF) but KDR/Flk-1 binds only VEGF. The cDNA encoding the soluble truncated form of Flt-1 cloned from a human endothelial cell library encodes the 6 N-terminal IgG-like extracellular ligand-binding domain but does not encode the transmembrane spanning region and intracellular tyrosine kinase domains. The recombinant soluble receptor binds avidly to VEGF and is a potent VEGF antagonist. Recently, a third VEGF receptor was identified and cloned from tumor cells. This VEGF receptor is isoform-specific, binding VEGF₁₆₅ but not VEGF₁₂₁. Studies indicate that this VEGF receptor (VEGF₁₆₅R) is identical to human neuropilin-1, a receptor for the collapsin/semaphorin family that mediates neuronal cell guidance.

EC₅₀ of 15-30 ng/ml in a cell proliferation assay using human umbilical vein endothelial cells

Lyophilized from sterile-filtered PBS, 300 mM NaCl, 50 µg BSA/µg of cytokine.

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

Reconstitute to ≥10 µg/ml with sterile PBS containing ≥0.1% HSA or BSA. It is recommended that the protein be titrated for optimal results in individual systems.

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Toxicity: Standard Handling (A)