HIGH-YIELD OF OSTEOINDUCTIVITY CAN BE DERIVED FROM DEMINERALIZED BONE-MATRIX USING COLLAGENASE DIGESTION

A bone morphogenetic protein purification method for minor quantities of bone material was developed based on collagenase splitting of bone connective tissue. Our aim was to remove and characterize the osteoind uctive protein preparation in native form without using strongly disso ciative agents. We started from 80 g of HCl-demineralized reindeer bon e material which was treated with type I collagen splitting collagenas e. The solution was dialyzed against 10 mM glycine-HCl buffer, pH 5.2. The formed precipitate was found to be osteoinductive. After fraction ation of the material using HPLC gel filtration it was observed that t he high-molecular-weight component of the precipitate was biologically active. Isoelectric focusing revealed that the component consisted of at least eight different protein molecules. Lower-molecular-weight co mponents induced no bone formation. These preliminary findings suggest that in native form at least one part of BMP is in a complex form and other extracellular matrix components bound to the osteoinductive pro tein complex are significant for BMP action and may act synergisticall y or as carriers for the BMP.