Being one tissue in the mammalian body that regenerates in postfetal life, bone is a promising tissue for research on morphogenetic matrix for osteogenetic gene expression. The proposed research deals with the following hypothetical constituents: the bone morphogenetic property (BMP), a poly-peptide found in a recently defined collagenase released fraction of the noncollagenous proteins of bone, dentin, and other calcified tissues; neutral proteinase (BMPase) closely associated with, but separable from, BMP; BMPase-inhibitor, soluble noncollagenous proteins; BMP-inhibitor, high molecular weight soluble protein. The investigative procedures are designed to separate and purify the constituents of the bone morphogenetic system by digestion of the EDTA-insoluble residue of bone matrix with collagenase. The methods include: 1.5 Agarose gel filtration of the collagenase digests, column chromatography with DEAE and other ion-exchangers; SDS acrylamide gel electrophoresis. The BMP is bioassayed in: (a) residues of matrix implanted in muscle in rats; (b) isolated fractions added to chemically defined culture media in vitro in systems consisting of$ mesenchymal cell outgrowths of muscle into cellulose; (c) isolated fractions implanted in double and triple walled millipore and nucleopore chambers in muscle pouches with and without minced muscle, or with or without disaggregated muscle mesenchymal cells; (d) isolated fractions immobilized in various nonimmunogenic nonbiologic polymers. BIBLIOGRAPHIC REFERENCES: Butler, W.T., Mikulski, A.J. and Urist, M.R.: Noncollagenous proteins which possess BMP activity. J. Dental Res. 55:74 only, Special Issue B. Abstr. Int. Assn. Dent. Res., March 25-28, Miami, FL, 1976. Mikulski, A.J., Butler, W.T. and Urist, M.R.: Noncollagenous proteins associated with bone morphogenetic activity. J. Dental Res. 55:1375 only, Special Issue B. Abstr. Int. Assn. Dent. Res. March 25-28, Miami, FL, 1976.