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, one being VEGF-120. and bovine VEGF are one amino acid shorter than the factor, and the bovine and sequences show a homology of 95%. Recombinant VEGF-120 is an alternative spliced version of VEGF-165. It is a non-glycosylated homodimer, containing two chains, with a molecular weight of 28.2 kDa.