The Divergence in Reactivity of Aminoacyl Transfer Ribonucleic Acid Synthetases of Escherichia coli with Hydroxylamine
Year: 1968
Type: article
Abstract: Fourteen partially purified Escherichia coli aminoacyl transfer ribonucleic acid synthetases were tested for their rates of amino acid hydroxamate formation relative to the rates of aminoacyl-tRNA formation. Three groups of reactivity were observed: tyrosyl-, phenylalanyl-, tryptophanyl-, and methionyl-tRNA synthetases catalyze hydroxamate formation at rates comparable to those for aminoacyl-tRNA formation; with lysyl-, alanyl-, isoleucyl-, glycyl-, cysteinyl-, leucyl-, seryl-, and valyl-tRNA synthetases, the relative rates of hydroxamate formation progressively decrease; and glutaminyl- and threonyl-tRNA synthetases do not catalyze hydroxamate formation. In an unfractionated enzyme extract, threonine hydroxamate forms, but this is totally accounted for by the mistaken activation of threonine by the valyl-tRNA synthetase. Purified threonyl-tRNA synthetase catalyzes hydroxamate formation only when tRNA is present, by catalyzing the formation of threonyl-tRNA, which reacts nonenzymatically with hydroxylamine. The mammalian threonyl-tRNA synthetase also fails to catalyze formation of threonine hydroxamate from amino acid and ATP.
Source: Journal of Biological Chemistry
Authors: D I Hirsh, F Lipmann
Institution: Rockefeller University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1514620408