Activity and solubility of bone morphogenetic protein derived from porcine bone matrix

Bone morphogenetic protein (BMP) was extracted from porcine bone matrix and purified by liquid chromatography. The final purified fraction was shown to be homogeneous by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis (SDS-PAGE). The molecular weight of porcine bone matrix-derived BMP was estimated to be about 20 kDa by SDS-PAGE. The final purified BMP was highly soluble in vivo, so that it dispersed immediately after implantation and exerted no effect on bone induction. The other crude active fractions obtained in the process of purification induced new bone in three weeks when implanted into muscle pouches of Wistar rats. These findings suggested that pure BMP requires an appropriate carrier (delivery system) for clinical use; hence, experiments using atelopeptide type-I collagen as carrier were conducted.