Biosynthesis of rat enamel matrix components in vivo.

The biosynthesis of enamel matrix components of developing rat incisors was investigated by measuring the incorporation of 3 H-proline, 32P-phosphate, and 35S-sulfate in vivo. 3H- and 32P-radioactivity was found in what seemed to be a prototype of enamel proteins. Subsequent shifts in other protein and peptide fractions were observed. 35S was also incorporated into components other than the above-mentioned proteins.