VEGF (121 a.a.) Human, Sf9

Vascular Endothelial Growth Factor (VEGF) is a critical signaling protein involved in both vasculogenesis and angiogenesis. The specific isoform, VEGF-121, is a splice variant of VEGF-A and plays a significant role in vascular endothelial cell survival, growth, migration, and vascular permeability .

VEGF-121 is a glycosylated polypeptide chain containing 121 amino acids, with a molecular mass of approximately 36 kDa when produced in insect cells (Sf9). It forms an 18 kDa homodimer . This isoform circulates more freely compared to other VEGF forms, which bind more tightly with vascular heparin sulfates .

VEGF-121 mediates increased vascular permeability, induces angiogenesis, vasculogenesis, and endothelial cell growth, promotes cell migration, and inhibits apoptosis. It has been shown to stimulate endothelial cell mitogenesis and cell migration in vitro . VEGF-121 binds to VEGFR1 and VEGFR2 receptor tyrosine kinases, leading to the activation of pathways involving PI3K/Akt, p38 MAPK, and FAK .

VEGF-121 is produced by various cell types, including endothelial cells, macrophages, and T cells. Its expression is induced by hypoxia, inflammatory cytokines, and oncogene products in tumors . Elevated levels of VEGF are linked to several pathological conditions, such as proliferative and nonproliferative diabetic retinopathy and POEMS syndrome .

Recombinant VEGF-121 is used extensively in research to study its effects on angiogenesis and vascular permeability. It is also utilized in cell proliferation assays using primary human umbilical vein endothelial cells (HUVECs), where it demonstrates significant bioactivity .

The recombinant VEGF-121 protein is typically supplied as a lyophilized powder. It is stable at room temperature for up to three weeks but should be stored desiccated below -18°C for long-term storage. Upon reconstitution, it should be stored at 4°C for short-term use (2-7 days) and below -18°C for long-term use. To prevent loss of potency, it is recommended to add a carrier protein (0.1% HSA or BSA) and avoid multiple freeze-thaw cycles .