Osteogenesis inhibitory protein: a (p)review

An historical perspective concerning biologically active factors derived from the organic matrix of bone is presented. The emphasis is upon the first discovered of these, bone morphogenetic protein (BMP) and a protein which copurifies with BMP in the initial steps of chemical fractionation. This newly described protein has the biological role of inhibiting the activity of BMP both in vivo and in vitro. Thus it has been named osteogenesis inhibitory protein (OIP). A summary of the known activities of this protein is presented along with preliminary data which indicate the antimitotic nature of OIP.