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Biomedical subjects

J Goldstein

Publications and source records attributed to J Goldstein.

At least 379 records · Page 21Linked to original sources

Peptide chain termination. VI. Purification and site of action of S.

PEPTIDE CHAIN TERMINATION IS A RESULT OF AT LEAST TWO EVENTS: terminator codon recognition and hydrolysis of peptidyl tRNA. A protein factor S, isolated from the supernatant of Escherichia coli B, stimulates fMet release. Factor S lowers the K(m) for terminator trinucleotides without altering the V(max) of release and therefore acts at terminator codon recognition. The S protein differs from initiation factors, elongation factor G, several forms of elongation factor T and release factors. The importance of the 2% Tu content in purified S is unresolved.

Bacterial Proteins↗

Peptide chain termination. 3. Stimulation of in vitro termination.

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.

Amino Acid Sequence↗