title: [Association of eukaryotic aminoacyl-tRNA-synthases with polyribosomes].
abstract: Upon fractionation of a mitochondria-free extract of rabbit reticulocytes into a ribosome-free extract and mono- and polyribosomes the bulk of the aminoacyl-tRNA synthetase activity was found in the fraction of mono- and polyribosomes. All the fifteen aminoacyl-tRNA synthetases were revealed, although in somewhat different quantities, in both fractions of the mitochondria-free reticulocyte extract. Aminoacyl-tRNA synthetases of the ribosome-free extract are found in two forms: RNA-binding one, and, the one having no affinity for high molecular weight RNAs. Aminoacyl-tRNA synthetases dissociated from the complexes with polyribosomes exist only in the RNA-binding form. All aminoacyl-tRNA synthetases can be removed from such complexes by an addition of 16S rRNA of E. coli, poly(U) or tRNA of rabbit reticulocytes. This testifies to labile association of aminoacyl-tRNA synthetases with the RNA-component of polyribosomes as well as to a rather nonspecific character of their interaction. After EDTA-induced dissociation of polyribosomes, the aminoacyl-tRNA synthetase activity was detected in the complex with both ribosomal subunits.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D002499:Centrifugation, Density Gradient; D002846:Chromatography, Affinity; D005057:Eukaryotic Cells / Q000201:enzymology / Q000378:metabolism; D066298:In Vitro Techniques; D011132:Polyribosomes / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000201:enzymology / Q000378:metabolism
chemical_list: D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases
vernacular_title: Assotsiatsiia éukarioticheskikh aminoatsil-tRNK-sintetaz s poliribosomami.