Systematic purification of free and matrix-bound phosphophoryns of bovine dentin: presence of matrix-bound phosphophoryn as a distinct molecular entity.
Free and matrix-bound phosphophoryns, both highly phosphorylated proteins in dentin, were prepared from EDTA extract and CNBr-digests of bovine dentin. The two components were purified by DEAE-cellulose, SP-Sephadex, and gel filtration chromatography. The matrix-bound component was eluted as a distinct peak from the free component in the above chromatographic systems. Amino acid composition of the purified matrix-bound component indicated that this component consisted of phosphophoryn and collagen in the ratio of 2:3 based on the number of the residues. The matrix-bound component could not be reconstituted by mixing phosphophoryn with collagen CNBr peptides. Artificial crosslink products of free phosphophoryn and collagen CNBr-peptides by the carbodiimide method showed similar properties to the physiological matrix-bound phosphophoryn. The bond between phosphophoryn and collagen of the matrix-bound component is assumed to be a covalent crosslink.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002417:Cattle; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D003094:Collagen / Q000378:metabolism; D003804:Dentin / Q000032:analysis*; D007180:Incisor; D010750:Phosphoproteins / Q000032:analysis / Q000302:isolation & purification* / Q000378:metabolism; D011485:Protein Binding
D000596:Amino Acids; D010750:Phosphoproteins; C017630:phosphophoryn; D003094:Collagen