title: The role of divalent cations in the reactions of valyl transfer ribonucleic acid synthetase of Escherichia coli. Effects of spermine and ethylenediaminetetraacetate.
abstract: We have analyzed the function of spermine in the aminoacylation of tRNA-Val by the valyl-tRNA synthetase of Escherichia coli. Our results indicate that Mg2+ is required for the aminoacylation reaction as well as for the ATP-PP-i exchange catalyzed by this enzyme. The apparent stimulation by spermine is a function of the tRNA used, which appears to contain bound cations even after dialysis against 10 minus 4 M EDTA. Higher concentrations of EDTA totally abolish spermine-stimulated esterification of tRNA-Val.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D013096:Spermine / Q000494:pharmacology*; D014637:Valine-tRNA Ligase / Q000378:metabolism*
chemical_list: D013096:Spermine; D004492:Edetic Acid; D000604:Amino Acyl-tRNA Synthetases; D014637:Valine-tRNA Ligase; D008274:Magnesium