Vascular Endothelial Growth Factor-A (VEGF-A) was originally isolated from tumor cells and is produced by a wide variety of cell types. In addition to stimulating vascular growth and vascular permeability, VEGF-A may play a role in stimulating vasodilation via nitric oxide-dependent pathways. VEGF-A has several variants, VEGF-165 being the most abundant. Recombinant VEGF 165 is a non-glycosylated homodimer, containing two 165 amino acids, with a total molecular weight of 38.2 kDa.