Synthesis of Paramecium surface proteins. I. Puromycin insensitive amino acid incorporation.

The synthesis of a surface protein has been studied in Paramecium through double-labeling experiments using [(14)C]- and [(3)H]leucine-labeled bacteria as the source of radioactive amino acid. Over a 4-5 h incubation period, the turnover rate was found to be higher than that of overall cell protein. In addition, the initial label is apparently utilized during the chase period, being incorporated into protein via a puromycin insensitive pathway.