Separation and purification of porcine bone morphogenetic protein.

Porcine bone morphogenetic protein (pBMP) was separated and purified from porcine bone by repeated solubilization and precipitation of the protein with different concentrations of urea and GuHCl. The molecular weight of pBMP was determined to be 19.7 k. The property of inductive osteogenesis of pBMP caused new bone formation in muscular and subcutaneous tissues of strain No. 615 mice. Osteoid tissues were observed as early as ten days after implantation of pBMP, and lamellated new bones with marrow cavities were first found on the 15th day of implantation. A gradual transformation of mesenchymal-type cells into active chondroblasts and osteoblasts and finally into heterotopic new bone was observed and studied histologically and ultrastructurally.