Human IGFBP-5

Human Insulin-like growth factor binding protein-5 (IGFBP-5) is a 252 amino acid protein which is a member of a family of six circulating proteins that bind IGF-I and IGF-II with high affinity and modulate their metabolic and mitogenic effects. Human IGFBP-5 preferentially binds to IGF-II and primarily inhibits the effects of IGF peptides. It can also form a ternary complex with the acid-labile sub-unit. It binds to extra-cellular matrix proteins which protect it from proteolysis and modify its biological functions. IGFBP-5 may also elicit a biological action through a non-IGF binding mechanism.