Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.
Biological Activity: Measured in a cell proliferation assay using HUVEC human umbilical vein endothelial cells. The ED50 for this effect is 4.711 ng/mL, corresponding to a specific activity is 2.123×105 units/mg.