The acidic macromolecules in rabbit cortical bone tissue.

Rabbit cortical bone powder was extracted with EDTA solutions at neutral pH and the soluble constituents fractionated by DEAE-cellulose chromatography. The acidic fractions obtained were further investigated by gel chromatography and chemical analysis. Two classes of proteoglycans were present; one containing chondroitin sulphate and the other containing material resembling keratan sulphate mixed with a smaller amount of chondroitin sulphate. Sialoglycoproteins were detected by specific chemical introduction of tritium label into the sialic acid residues of the acidic glycoprotein fraction. Following sodium dodecyl sulphate-polyacrylamide gel electrophoresis and fluorography, the presence of numerous distinct sialoglycoprotein components was demonstrated.