Solubilized and insolubilized bone morphogenetic protein.

TLDR

BMP can be extracted in solution from demineralized rabbit cortical bone matrix using bacterial collagenase and remains biologically active in a neutral salt/ethylene glycol mixture. BMP can be insolubilized by coprecipitation with calcium phosphate and later resolubilized with a neutral salt in the same solvent, and it binds to concanavalin A‑Sepharose via hydrophobic and carbohydrate interactions, allowing recovery by elution with alpha‑methyl mannoside or ethylene glycol. Implants of the BMP eluates and coprecipitate extracts in diffusion chambers trigger transmembrane bone morphogenesis, the protein is not species specific—rabbit BMP induces bone in rats—and it is a glycoprotein.

Abstract

A bone morphogenetic protein (BMP) obtained in solution by digestion of demineralized rabbit cortical bone matrix with bacterial collagenase retains its biologically active conformation in a neutral salt/ethylene glycol mixture. BMP may be insolubilized by coprecipitation with calcium phosphate and resolubilized by chemical extraction with a neutral salt in the same solvent mixture. Upon concanavalin A-Sepharose chromatography, BMP is bound by hydrophobic interaction and carbohydrate recognition and is recovered by elution with either alpha-methyl mannoside or ethylene glycol solvent mixture. Implants of both eluates and the extracts of the coprecipitate in double-walled diffusion chambers induce transmembrane bone morphogenesis. BMP is not species specific; rabbit BMP induces new bone formation in the rat. The present observations indicate that BMP is a glycoprotein.