title: [Translation of poly U by ribosomes from rel+ and rel- E. coli strains].
abstract: A translation of polyU in a cell-free system from CP78 (relA+) and CP79 (relA-) E. coli strains is investigated. The strains studied no not differ in misreading at Mg2+ concentration of 20 mM and concentrations of 16 mM (optimal for phenylalanine incorporation) and 18-22 mM (optimal for leucine incorporation) respectively. It is found that leucine incorporation increases similarly in both strains under conditions simulating an amino acid deficience (in phenylalanine-free incubation medium): the ratio leucine(-phenylalanine)/leucine (+phenylalanine) is 3.5-4 at a concentration of enzymatic fraction protein being 15-30 mkg per example, and it is 2 st a concentration of enzymatic fraction of 60-180 mkg of protein. It is suggested that differences in activities of a number of enzymes under amino acid starvation in Rel+ and Rel- cells are not due to differences in the precision of mRNA translation, but depend on the activity of respective genes.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D002474:Cell-Free System; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D011072:Poly U / Q000378:metabolism*; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000378:metabolism; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D011072:Poly U; D007930:Leucine; D008274:Magnesium
vernacular_title: Transliatsiia poli-U ribosomami iz kletok rel+ i rel- -shtammov E. coli.