ABSTRACT
This chapter presents the subject matter to the correlation of codon usage of three microorganisms to transfer ribonucleic acid (tRNA) content and related topics. The cellular tRNA content of E. coli, Salmonella typhimurium, and Saccharomyces cerevisiae was measured and the organism-specific codon-choice patterns of these microorganisms were attributed to the availability of tRNA isoacceptors within a cell. Using two-dimensional polyacrylamide gel electrophoresis, tRNAs can be separated with a high degree of resolution. The usage frequency of a tRNA responding to a single codon was defined as the occurrence of the codon itself, and that of a tRNA responding to multiple codons as the total occurrence of the corresponding codons. A close correlation between codon usage and tRNA population should have resulted from the accumulation of a great number of mutations and successive base substitutions in both protein and tRNA genes during evolution.
