TRAIL (TNF-related apoptosis-inducing ligand) is a cytokine that is produced and secreted by most normal tissue cells. TRAIL binds to cell surface death receptors DR4 and DR5, by which it activates caspase-8 to induce apoptosis of cancer cells but not of normal cells. This product contains the extracellular domain (amino acids 95-281) of full-length human TRAIL and it is competent for binding of DR4 and DR5.This product has been tested for inducing apoptosis of TRAIL-sensitive cancer cell lines at concentrations of 1-50 ng/mL.