Stem cell factor/KIT ligand (SCF) is a cytokine which binds CD117 (c-Kit). SCF is also known as "steel factor" or "c-kit ligand". SCF exists in two forms, cell surface bound SCF and soluble (or free) SCF. Soluble SCF is produced by the cleavage of surface bound SCF by metalloproteases.SCF is a growth factor important for the survival, proliferation, and differentiation of hematopoietic stem cells and other hematopoietic progenitor cells. One of its roles is to change the BFU-E (burst-forming unit-erythroid) cells, which are the earliest erythrocyte precursors in the erythrocytic series, into the CFU-E (colony-forming unit-erythroid).Source:Recombinant protein corresponding to rat Stem Cell Factor, a single, non-glycosylated polypeptide chain containing 165aa, expressed in E. coli. Molecular Weight: ~18.4kDBiological Activity:The ED50, calculated by the ability to inhibit 5ng/ml of BMP-4 induced alkaline phosphatase production by ATCD-5 chondrogenic cells, is <0.06ug/ml. AA Sequence: The sequence of the first five N-terminal amino acids was determined and was found to be Met-Glu-Gly-Ile-Cys. Protein Content: Protein quantitation was carried out by two independent methods: 1. UV spectroscopy at 280nm using the absorbency value of 0.52 as the extinction coefficient for a 0.1% (1mg/ml) solution. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics). 2. Analysis by RP-HPLC, using a standard solution of Stem Cell Factor as a Reference Standard. Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months after receipt at -20°C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months 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.