Comparison of the codon recognition properties and of the utilization of normal and tumor specific Phe-tRNAs in protein synthesis.

Phe-tRNA from normal rat liver (designated Phe-tRNAN) and the under-modified, tumor specific, Phe-tRNAs from mouse neuroblastoma (designated Phe-tRNANB) and rat lymphoma (designated Phe-tRNARL) recognize the phenylalanine codons, UUU and UUC in a ribosome binding assay, but not other codons that differ from UUU and UUC in a single base at either the 5' or 3' position. Phe-tRNANB was incorporated into protein more extensively than either Phe-tRNARL or Phe-tRNAN in wheat germ extracts programmed with globin mRNA. The utilization level of each Phe-tRNA was correlated with its rate of deacylation in wheat germ extracts, i.e., Phe-tRNANB deacylated less rapidly than Phe-tRNARL or Phe-tRNAN. Phe-tRNA, from which the Y base was chemically excised (designated Phe-tRNA-Y), did not respond to UUU or UUC in the ribosomal binding assay, nor did it transfer its phenylalanine to protein in wheat germ extracts programmed with globin mRNA.