BMP-2 is one of fifteen bone morphogenetic proteins (BMP) belonging to the TGF- beta superfamily. The BMPs were first identified as the active factors in demineralized bone matrix, with transcripts later being discovered in many other types of tissue. They are synthesized as large precursor molecules that must be cleaved into their active form and dimerize in order to exhibit functional activity. These dimers may include two identical or distinct BMP chains. BMP responsiveness appears to be limited to multipotent and immature cells. The BMPs are essential for osteogenesis and organogenesis during embryonic development, and also play a role in fracture and wound healing in adults.