ABSTRACT
This chapter examines the phenomenon in the cells and tissues of higher eukaryotes. The adaptation of the cellular transfer ribonucleic acid (tRNA) population to its requirements for protein synthesis has been examined at two different cellular levels. The most extensively studied cell types in higher eukaryotes with respect to comparing the isoacceptor levels and the cognate codon frequencies within mRNAs are the silk gland of Bombyx mori and the reticulocytes of rabbits and humans. Clearly, the aminoacyl-tRNA population in cells is adapted to its requirements for protein synthesis. The tRNA population in Friend leukemia cells has been examined before and after induction of erythroid differentiation. The actual amounts of tRNA isoacceptors present in any given cell would then be determined by the demands of protein synthesis which would then invoke another set of regulatory mechanisms within that particular cell.
