title: Peptide chain termination. 3. Stimulation of in vitro termination.
abstract: Throughout extensive purification, the release factors R(1) and R(2) each behave as a single molecular species with alternate codon recognition (R(1), UAA or UAG; R(2), UAA or UGA). The release of f[(3)H]methionine from f[(3)H]-Met-tRNA.AUG.ribosome complex requires R factor and terminator codon and does not appear to require tRNA or transfer factors T and G. Purification of the components of the release assay has enabled identification of a protein factor S in the 55-80 per cent ammonium sulfate fraction of E. coli B supernatant fraction which stimulates the rate but not the extent of release dependent upon R factor and appropriate termination codon. The S factor has properties similar to T, but further purification is required to determine the nature and function of S in peptide chain termination.
mesh_terms: D000595:Amino Acid Sequence; D002845:Chromatography; D004926:Escherichia coli; D005815:Genetic Code; D008715:Methionine / Q000378:metabolism; D008722:Methods; D008967:Molecular Biology; D010455:Peptides; D012343:RNA, Transfer; D012270:Ribosomes; D014316:Tritium
chemical_list: D010455:Peptides; D014316:Tritium; D012343:RNA, Transfer; D008715:Methionine