Stem cell factor (SCF), also known as c-kit ligand (KL), mast cell growth factor (MGF), and steel factor (SLF), is a widely expressed 28 - 40 kDa type I transmembrane glycoprotein. It promotes the survival, differentiation, and mobilization of multiple cell types including myeloid, erythroid, megakaryocytic, lymphoid, germ cell, and melanocyte progenitors.
Specifications and Use for R&D SCF
Source of R&D SCF
• A DNA sequence encoding the extracellular domain human SCF (Glu 26 - Ala 189; Accession # 134289) (Martin, F.H. et al., 1990, Cell 63:203 - 211) was expressed in E. coli.
Molecular Mass of Recombinant SCF
• The 165 amino acid residue recombinant protein has a predicted molecular mass of approximately 18.6 kDa.
Purity of R&D SCF
• > 97%, as determined by SDS-PAGE and visualized by silver stain.
• < 1.0 EU per 1 μg of the cytokine as determined by the LAL method.
Activity of R&D SCF
• The biological activity of recombinant human stem cell factor was measured in a cell proliferation assay using a human factor-dependent cell line, TF-1 (Kitamura, T. et al., 1989, J. Cell Physiol. 140:323 - 334).
• The ED50 for this effect is typically 2.5 - 10 ng/mL. The cell number is assessed in a fluorometric assay using the redox sensitive dye, Resazurin (R&D Systems, Catalog # AR002).
• Lyophilized from a 0.2 μm filtered solution in PBS containing 50 μg of bovine serum albumin per 1 μg of cytokine.
Reconstitution of R&D SCF
• It is recommended that sterile phosphate-buffered saline containing at least 0.1% human serum albumin or bovine serum albumin be added to the vial to prepare a stock solution containing no less than 10 μg/mL of cytokine.
Storage of R&D SCF
• Lyophilized samples are stable for up to twelve months from date of receipt at -20° C to -70° C.
• Upon reconstitution, this cytokine can be stored under sterile conditions at 2° - 8° C for one month or at -20° C to -70° C in a manual defrost freezer for three months without detectable loss of activity.
• Avoid repeated freeze-thaw cycles.