Recombinant Human VEGF/PlGF Heterodimer Protein

The disulfide-linked homodimeric proteins vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) are both members of the VEGF family of growth factors. VEGF and PlGF proteins share primary structural as well as limited amino acid sequence homology with the A and B chains of PDGF. All eight cysteine residues involved in intra- and inter-chain disulfides are conserved among these growth factors. In their PDGF-like regions, VEGF and PlGF also share approximately 53% amino acid sequence similarity. E. coli-expressed monomers of PlGF and VEGF can be refolded in vitro to form PlGF/VEGF heterodimers. The purified recombinant VEGF/PlGF heterodimers and VEGF homodimers have potent mitogenic effects on endothelial cells. However, VEGF/PlGF heterodimers display approximately 50-fold less mitogenic activity than VEGF homodimers. In contrast, PlGF homodimers have little or no mitogenic effect on endothelial cells. The presence of natural VEGF/PlGF heterodimers in the conditioned media of a number of human tumor cell lines has been demonstrated using a VEGF/PlGF heterodimer specific ELISA.