Partial purification of bone-inducing substances from a murine osteosarcoma.

Bone-inducing substance from a murine osteosarcoma (BFO osteosarcoma) was partially purified by biochemical procedures, i.e., extraction by 4M Gu-HCl, fractionation by ethanol, precipitation in neutral buffer solution with low ionic strength and two steps of gel filtration. The yield of the final preparation was 2 mg from 10 g (wet weight) of BFO osteosarcoma. The preparation constantly induced ectopic bone in situ when implanted into allogenic mice. SDS polyacrylamide electrophoresis revealed that the biologically active fraction contained two distinct substances, the molecular weights of which were 19,500 and 22,500, respectively. Further purification of the bone-inducing substance is now in progress.