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Macromolecular complex of aminoacyl-tRNA synthetases from sheep liver. Identification of the methionyl-tRNA synthetase component by affinity labeling
- Source :
- European journal of biochemistry. 124(3)
- Publication Year :
- 1982
-
Abstract
- Both the tRNA aminoacylation and amino-acid-dependent ATP-PPi exchange activities of monomeric trypsin-modified methionyl-tRNA synthetase from sheep liver are lost upon incubation with oxidized initiator tRNAMet. The inactivation, which reflects the formation of a Schiff's base between the 5'-terminal adenosine of tRNA and a lysine within the catalytic site of the enzyme, is accompanied by the covalent attachment of one tRNA molecule per enzyme molecule. The affinity labeling method is applied to the sheep liver complex of Mr 10(6) carrying seven aminoacyl-tRNA synthetase activities, from which the monomeric trypsin-modified methionyl-tRNA synthetase (Mr 68 000) was derived. Upon incubation with oxidized initiator tRNAMet, the methionyl-tRNA synthetase activity of the complex is lost. Of the eleven polypeptide chains composing the high-molecular-weight complex, only one polypeptide chain with Mr 103 000 reacts with the modified tRNAMet. The blocking by periodate-treated tRNA of the methionyl-tRNA synthetase activity in the complex has no effect on the other aminoacyl-tRNA synthetase activities. This strongly argues in favor of the independent parallel functioning of the seven aminoacyl-tRNA synthetases associated in a high-molecular-weight complex.
- Subjects :
- Chemical Phenomena
Macromolecular Substances
Lysine
Methionine-tRNA Ligase
Biology
In Vitro Techniques
Biochemistry
Amino Acyl-tRNA Synthetases
chemistry.chemical_compound
medicine
Escherichia coli
TRNA aminoacylation
Animals
Trypsin
chemistry.chemical_classification
Affinity labeling
Sheep
Aminoacyl tRNA synthetase
Hydrolysis
Periodic Acid
Affinity Labels
Adenosine
Chemistry
Kinetics
Enzyme
chemistry
Liver
Transfer RNA
medicine.drug
Subjects
Details
- ISSN :
- 00142956
- Volume :
- 124
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- European journal of biochemistry
- Accession number :
- edsair.doi.dedup.....d8a5730939318fc4c47b6c832caa2b7b