Noncollagenous phosphoprotein derived from teleostean fish-scales

A noncollagenous phosphoprotein derived from teleostean fish-scales is extracted by the use of a dissociative extraction scheme, utilizing 4 M guanidine-HCl, pH 7.4, followed by a 4 M guanidine-HCl, 0.5 M EDTA, pH 7.4. DEAE-cellulose chromatography and repeated Sepharose CL-6B chromatography are used to purify this protein. The isolated protein contains extensive quantities of aspartic and glutamic acids in addition to O-phosphoserine and O-phosphothreonine. The apparent molecular weight of the phosphoprotein as determined by Sepharose CL-6B chromatography is 13 000.