Open AccessEnzymatic Deacylation of Methionyl‐tRNA f Mef Catalysed by Methionyl, Isoleucyl and Phenylalanyl‐tRNA Synthetases
Author(s) -
SOURGOUTCHOV Andrei,
BLANQUET Sylvain,
FAYAT Guy,
WALLER JeanPierre
Publication year - 1974
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1974.tb03636.x
Subject(s) - transfer rna , enzyme , trypsin , spermidine , biochemistry , escherichia coli , stereochemistry , biology , chemistry , rna , gene
Native and trypsin‐modified methionyl, isoleucyl and phenylalanyl‐tRNA synthetases from Escherichia coli catalyze the deacylation of methionyl‐tRNA t Met . This activity, which is pH dependent, requires the presence of MgCl 2 or spermidine which are known to structure the aminoacyl‐tRNA. Investigation of the effects of cognate amino acids on the rate of enzymatic deacylation of methionyl‐tRNA t Met , reveals strikingly different behaviours of native and trypsin‐modified methionyl‐tRNA synthetases. Kinetic parameters for the deacylation of methionyl‐tRNA t met catalyzed by native methionyl and isoleucyl‐tRNA synthetases are compared in the presence of MgCl 2 and provide identical K m values of 0.2 μM while their V values, are 0.05 and 0.02 s −1 , respectively. This indicates similar enzymatic efficiencies per active site and emphasizes the lack of specificity of the reaction.