<p>The present invention provides an osteogenically active protein preparation characterized by a molecular weight of from about 31,000 to 34,000 daltons as characterized comprising a subunit identical to or homologous to a subunit in P3 OF 31-34, by non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis and by the characteristic of eluting from a reverse phase high performance liquid chromatography column equilibrated with buffers containing trifluoroacetic acid and acetonitrile by eluting within the concentrations of 35% to 45% acetonitrile. The invention further provides improved methods for isolating such preparations and genes encoding all or a portion of polypeptide subunits of dimers comprising the osteogenic protein preparation.</p>
