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Risk of CVD and mortality due to CKD needs to be stratified according to the underlying renal diseases.

Erythromycin A released peptidyl-tRNA in the in vitro polypeptide synthesis system with bacterial components programmed by synthetic polynucleotide. This is consistent with our hypothesis that erythromycin A inhibits translocation by preventing proper situation of oligopeptidyltRNA in the donor (D) site on ribosomes.Erythromycin A has been shown to inhibit the translocation step (1-3) as well as the peptidyl transferase step (4) of polypeptide formation. In an attempt to correlate these observations, a unitary hypothesis was proposed in which erythromycin inhibits translocation by preventing polypeptidyltRNA from situating itself properly at the donor (D or P) site while it would still allow the movement of the polypeptidyltRNA to the vicinity of the D-site (1).One logical extension of the above hypothesis is that peptidyl-tRNA which was hindered by erythromycin from situating itself correctly at the D site might well be unstable and would, therefore, be released from ribosomes. This communication presents evidence that this is indeed the case. Erythromycin A releases oligopeptidyl-tRNA from ribosomes in an in vitro protein synthesizing system. This finding correlates with the accumulation of oligopeptide in the presence of erythromycin A (5, 6), as well as instability of ribosomal complexes blocked by erythromycin (20). MATERIALS AND METHODSEscherichia coli Extract and Other Materials. E. coli Q13 (middle of the logarithmic phase of growth) was purchased from General Biochemicals Co. Preparations of soluble enzymes, S-150 (8), and ribosomes (9) were described previously. Soluble enzymes free of peptidyl-tRNA hydrolase were prepared as described elsewheret. The sources of the antibiotics were described previously (1, 8,10,11 2649A, the ratio of released polyphenylalanine to that bound to ribosomes increased at least 4-fold, indicating that release of polyphenylalanine takes place in the presence of this antibiotic. In confirmation of previous results (1), erythromycin had only a slight effect on the overall polyphenylalanine synthesis.Since it is known that oligolysine accumulates in the presence of erythromycin A (5), the possibility that oligolysyltRNA is released from ribosomes in the presence of erythromycin A was also examined. In the experiment shown in Table 2, erythromycin A was added to a polylysine synthesis system and the released materials were analyzed by paper chromatography to separate oligolysine from mono-and polylysine (12). It is clear from this table that the amounts of released dilysyl-and trilysyl-tRNA were markedly increased in the presence of erythromycin A, while in the presence of micrococcin, which is known to fix aminoacyl-tRNA to ribosomes (11), no appreciable release of oligolysyl-tRNA was observed.In order to establish the nature of the material which is released from ribosomes, the radioactive material in the soluble fraction was subjected to sucrose gradient centrifugation. As shown in Fig. 1, the peak of the radioactivity was found at the position where [14C]lysyl-tRNA ...

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