Recombinant Human Stem Cell Factor (SCF) contains 165 AAs^ Recombinant Human Stem Cell Factor (SCF) contains 165 AAs, with a MW of 18.4 kDa Activity: dose-dependent stimulation of Human TF-1 cells and is typically 1-5 ng/mL. Source: E.coli, Synonyms: c-Kit Ligand, KL, Steel Factor, mgF, 1MG