Functional significance of aminoacyl-tRNA synthetase complex in the aminoacylation of tRNA(Leu) isoacceptors.
Aminoacyl-tRNA synthetases, partially purified from rat liver by two different methods, were used in vitro to study aminoacylation profiles of tRNA(Leu) isoacceptors. On the basis of molecular weights, one preparation was similar to the multienzyme complex of aminoacyl-tRNA synthetases, whereas the other apparently represents a partially disrupted complex. In the aminoacylation assay, the multienzyme complex produced a profile of leucyl-tRNA isoacceptors that was similar to those found in vivo and in liver perfusion experiments. The aminoacylation profile that was obtained with the partially disrupted complex varied with the enzyme and leucine concentration used. Especially one of the tRNA(Leu) species was poorly aminoacylated at low leucine and enzyme concentration. These experiments point out that attention should be paid to the nature of the aminoacyl-tRNA synthetase preparation in experiments in which isoacceptor profiles are studied in vitro.
Department of Biochemistry, University of Kuopio, Finland.
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D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D006358:Hot Temperature; D066298:In Vitro Techniques; D007930:Leucine / Q000378:metabolism; D007935:Leucine-tRNA Ligase / Q000302:isolation & purification / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D012345:RNA, Transfer, Amino Acid-Specific / Q000378:metabolism*; D012356:RNA, Transfer, Leu / Q000378:metabolism*; D051381:Rats; D013329:Structure-Activity Relationship; D046249:Transfer RNA Aminoacylation
D046911:Macromolecular Substances; D009097:Multienzyme Complexes; D012345:RNA, Transfer, Amino Acid-Specific; D012356:RNA, Transfer, Leu; D000604:Amino Acyl-tRNA Synthetases; D007935:Leucine-tRNA Ligase; D007930:Leucine