Figure 5. Incorporation of m-[¹⁴C]tyrosine into proteins by a cell-free transcription/translation system.

Incorporation of m-[¹⁴C]tyrosine into luciferase protein was monitored using a cell-free reticulate lysate preparation containing the 20 common amino acids required for protein synthesis and either L-[¹⁴C]tyrosine or m-[¹⁴C]tyrosine. Radiolabelled protein was detected by SDS/PAGE and autoradiography. Lane A, amino acid mixture+L-[¹⁴C]tyrosine; lane B, amino acid mixture lacking L-tyrosine+m-[¹⁴C]tyrosine; lane C, amino acid mixture lacking L-phenylalanine+m-[¹⁴C]tyrosine. LUC, luciferase. Molecular-mass sizes are indicated in kDa.