[The mechanism of the reaction forming tryptophanyl-tRNA, catalyzed by tryptophan:tRNA-ligase].

The rates of tryptophanyl-tRNA formation catalyzed by beef pancreas tryptophanyl-tRNA synthetase were measured in a concentration range of each substrate (tryptophan, ATP and yeast tRNATrp) and also in the presence of various concentrations of substrate analogues (tryptamine and alpha,beta-methylene analogue of ATP) concentrations. The data obtained were compared with the kinetic equations which described various possible mechanisms of the reaction. The comparison of the mechanisms was based on the calculation of relative probabilities of each hypothesis the efficiency of which was demonstrated earlier. The calculations have shown that two mechanisms according to which the intermediate enzyme-aminoacyl-adenylate complex formation involves the enzyme-aminoacyl-tRNA complex are the most probable ones.