Recombinant Human Stem Cell Factor is a single, non-glycosylated, polypeptide chain containing 165aa and having a molecular weight of 18.4kD. The sequence of the first five N-terminal amino acids was determined to be Met-Glu-Gly-Ile-Cys. Contains less than 1% dimers and aggregates.Biological Activity:The ED50 as determined by the dose-dependent stimulation of Human TF-1 cells is <2ng/ml, corresponding to a specific activity of 5x10e5 IU/mg.Endotoxin: ≤0.1ng/ugStorage and Stability:Lyophilized powder may be stored at -20°C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.