THE USE OF CARBON-14 LABELLED AMINO ACIDS FOR DETECTING PROTEIN SYNTHESIS IN SUBCELLULAR PARTICLES OF MAMMALIAN TISSUES

A search was made for a simple biological system for the study of protein synthesis. Preparations were made of subcellular fractions from tissues involved in the synthesis of the specific proteins of interest. The energy- dependent incorporation of carbon-14 labeled amino acids into the specific proteins was used as a criterion for the synthesis of protein by the cell preparations. When microsomes isolated from regenerating rat liver were incubated with labeled amino acids in the presence of a suitable source of energy the serum albumin contained within the microsomal membrane became radioactive. Results are compatible with the hypothesis that isolated liver microsomes are able to synthesize a specific protein, but further work is needed to test this hypothesis. (C.H.)