Angiopoietin-like 5 (ANGPTL5), also called angiopoietin-like protein 5 or angiopoietin-related protein 5, is a secreted factor with high homology to angiopoietins which are important regulators of angiogenesis. Angiopoietins bind to the angiopoietin-specific receptor TIE-2, whereas angiopoietin-like proteins do not bind to this receptor. The receptor for ANGPTL5 is not yet known. Due to a coiled-coil domain, which can interact with the extracellular matrix, they exist primarily as homooligomers. Angiopoietin-like proteins are potent regulators of angiogenesis either proangiogenic or antiangiogenic factors, suggesting that their receptors may be expressed on endothelial cells. They also show pleiotropic effects on cells of other lineages, such as skin cells and chondrocytes. Angiopoietin-like proteins play a role in lipid and triglyceride metabolism and vertebrate development. It has been shown that ANGPTL5 stimulates the

expansion of human cord blood hematopoietic stem cells.

cytokines are suitable for a wide variety of cell culture applications. They are sterile-filtered prior to lyophilization. Generally, endotoxin levels are <0.1 ng/μg (<1 EU/μg), and purities are >95%. The biological activity is tested in appropriate bioassays.