Molecular Weight: Approximately 18.4 kDa, a single non-glycosylated polypeptide chain containing 165 amino acids.Purity: >97% by SDS-PAGE and HPLC analyses.Biological Activity: Fully biologically active when compared to standard. The ED50 as calculated by the dose-dependant stimulation of the proliferation of human TF-1 cells is less than 3 ng/ml.Physical Appearance: Sterile Filtered White lyophilized (freeze-dried) powder.Formulation: Lyophilized from a 0.2μm filtered concentrated (1mg/ml) solution in PBS, pH 7.4.Endotoxin: Less than 1EU/μg of rHuSCF as determined by LAL method.Reconstitution: We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/ml. Stock solutions should be apportioned into working aliquots and stored at Storage: This lyophilized preparation is stable for several weeks at 2-8°C, but should be kept at -20°C for long term storage, preferably desiccated. Upon reconstitution, the preparation is stable for up to one week at 2-8°C. For maximal stability, apportion the reconstituted preparation into working aliquots and store at -20°C to -70°C. Avoid repeated freeze/thaw cycles.Usage: This material is used for research, laboratory or further evaluation purposes. NOT FOR HUMAN USE. Human Stem Cell FactorC-kit ligand, the recently identified ligand for the kit tyrosine kinase receptor, is mapped to the mouse S1 locus. This pleiotropic cytokine, alternately known as stem cell factor (SCF), mast cell growth factor (MGF) and steel-factor (SLF), plays essential roles in gametogenesis, melanogenesis and early stages of hematopoiesis. In vitro and in vivo, SCF can stimulate the proliferation of mature, as well as the proliferation and maturation of immature, mast cells. On purified primitive human and mouse hematopoietic precursors, SCF acts in a synergistic manner with various growth factors, such as IL-1, IL-3, IL-6, IL-7, and Epo, to induce myeloid, erythroid and lymphoid lineage colony formation. The finding that SCF is also expressed in the nervous system suggests a possible role for SCF in the development of the nervous system.