OSTEOINDUCTIVE PROTEIN MIXTURES AND PURIFICATION PROCESSES

摘要

A method for purifying bone-derived osteoinductive factors including an ultrafiltration process, an anion exchange process, a cation exchange process, and a reverse phase HPLC process. The ultrafiltration process preferably includes a first ultrafiltration step using a membrane having a nominal molecular weight cutoff of approximately 100 kilodaltons (kD) and a second ultrafiltration step employing a membrane having a nominal molecular weight cutoff of approximately 10 kD. For the anion exchange process, a strongly cationic resin is used, preferably having quaternary amine functional groups. Typically, the eluant for the anion exchange process has a conductivity from about 10,260 micromhos ( mu mhos) (1.026x10-2 siemens (S)) to about 11,200 mu mhos (1.120x1031 2 S). For the cation exchange process, a strongly anionic resin is used, preferably having sulfonic acid functional groups. The eluant for the cation exchange process typically has a conductivity from about 39,100 mu mhos (3.91x10-2 S) to about 82,700 mu mhos (8.27x10-2 S) or more. The HPLC process typically utilizes a column containing hydrocarbon-modified silica packing material. The osteoinductive proteins can be eluted from the HPLC column with an acetonitrile solution in combination with aqueous trifluoracetic acid. The purification processes yield osteoinductively active protein mixtures.