Hydrocortisone induction of rat-liver leucyl-transfer RNA and its synthetases.

Stoichiometry and composition of an aminoacyl-tRNA synthetase complex from rat liver.

The particulate aminoacyl-tRNA synthetases of rat liver were copurified about 1000-fold with more than 20% yields for individual synthetase activities. Measurements of aminoacylation activities showed that lysyl-, arginyl-, leucyl-, isoleucyl-, and methionyl-tRNA synthetases in the purified complex cosedimented at 18 S. The molecular weight of the synthetase complex is about one million, as est...

Isolation and partial characterization of temperature-sensitive Escherichia coli mutants with altered leucyl- and seryl-transfer ribonucleic acid synthetases.

Two temperature-sensitive mutants of Escherichia coli have been found in which the conditional growth is a result of a thermosensitive leucyl-transfer ribonucleic acid (tRNA) synthetase and seryl-tRNA synthetase, respectively. The corresponding genetic loci, leuS and serS, cotransduce with lip and serC, respectively. As a result of the mutationally altered leucyl-tRNA synthetase, some leucine-,...

Regulation of synthesis of the aminoacyl-transfer ribonucleic acid synthetases for the branched-chain amino acids of Escherichia coli.

The regulation of synthesis of valyl-, leucyl-, and isoleucyl-transfer ribonucleic acid (tRNA) synthetases was examined in strains of Escherichia coli and Salmonella typhimurium. When valine and isoleucine were limiting growth, the rate of formation of valyl-tRNA synthetase was derepressed about sixfold; addition of these amino acids caused repression of synthesis of this enzyme. The rate of sy...

More evidence for a particle character of aminoacyl-transfer RNA synthetases isolated from rat liver.

Evidence for one leucyl transfer ribonucleic acid synthetase with specificity for leucine transfer ribonucleic acids with different coding characteristics.

Leucyl transfer ribonucleic acid synthetase (EC 6.1.1.4, L-leucine: tRNA ligase (AMP)) has been purified from Escherichia coli and is free of other aminoacyl-tRNA synthetases, tRNA-methylating enzymes, and CpCpA-adding enzymes. Several criteria suggest that there is one synthetase with specikity for two forms of leucine-specik tRNA which can be separated by countercurrent distribution: purifica...