Evidence That the Majority of Leucine Transfer Ribonucleic Acid Is Not Involved in Repression in Salmonella typhimurium

Leucine transfer ribonucleic acid (tRNA) was almost fully charged, and the isoleucine-valine and leucine enzymes remained derepressed when trifluoroleucine was added to a leucine auxotroph. High levels of charged leucine tRNA and derepression were also found in a leucyl-tRNA synthetase mutant.