A study of the bone morphogenetic protein derived from bovine demineralized dentin matrix

We tried to extract and purify bone morphogenetic protein (BMP) from bovine demineralized dentin matrix (DDM). Crude dentin BMP (d-BMP) was extracted from DDM in 3 sequential steps. Purification of crude d-BMP was carried out by liquid chromatography. The molecular weight and the isoelectric point of the purified d-BMP were determined by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electrofocusing. All fractioned samples were bioassayed in the thigh muscle pouches of AKR strain mice to test their ability to induce new bone formation. A sequence of 3 extraction steps worked effectively to obtain crude d-BMP. The purified d-BMP was shown to be homogeneous on high performance liquid chromatography (HPLC) and SDS-PAGE. The molecular weight and the pI were 25 kDa and 6.5, respectively. The amino acid composition was different from that of known bone-derived BMP. The purified d-BMP induced new bone formation in the thigh muscle pouches. The molecular weight, pI and amino acid composition were different from those of bone-derived BMP.