title: On the mechanism of tRNATrp aminoacylation catalysed by beef tryptophanyl-tRNA synthetase using presteady-state kinetics.
abstract: The dimeric tryptophanyl-tRNA synthetase from beef pancreas has been found to activate 2 tryptophans/mol enzyme [Eur. J. Biochem. (1982) 128, 389-398]. By using quenched-flow and stopped-flow methods under presteady-state conditions, we show that only one enzyme subunit operates at a time in the aminoacylation of tRNATrp and that the transfer reaction is not the rate-limiting step in the overall aminoacylation process.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D002417:Cattle; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D008956:Models, Chemical; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D014369:Tryptophan-tRNA Ligase / Q000378:metabolism*
chemical_list: D012346:RNA, Transfer, Amino Acyl; D000604:Amino Acyl-tRNA Synthetases; D014369:Tryptophan-tRNA Ligase