Biosynthesis of phosphoprotein by rat incisor odontoblasts in in-vitro culture

A tissue culture system consisting of odontoblasts still attached to predentine and dentine was developed to study dentinogenesis. After incubating the odontoblasts with both [ 3H]-serine and [ 33P]-phosphate for 24 h, the protein components were extracted with 0.5 M EDTA. A major component synthesized by the odontoblasts was identified as the phosphoprotein by double labelling with [ 3H]-serine and [ 33P]-phosphate and by co-elution in two chromatographic systems with unlabelled, carrier phosphoprotein.