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. 1972 Jul;69(7):1796–1799. doi: 10.1073/pnas.69.7.1796

Polypeptide Chain Initiation in Eukaryotes: Functional Identity of Supernatant Factor from Various Sources*

Michael Zasloff 1, Severo Ochoa 1
PMCID: PMC426804  PMID: 4558658

Abstract

Eukaryotic cells contain polypeptide chain initiation factors that, like the prokaryotic initiation factor IF-2, promote the AUG-dependent binding of fMet-tRNAf to the small ribosomal subunit. The bound amino-acyl-tRNA is directly convertible to fMet-puromycin upon addition of 60S subunit. The reaction is sensitive to initiation inhibitors such as aurintricarboxylic acid and edeine but, unlike its prokaryotic counterpart, it does not require GTP. Factors that catalyze the binding and fMet-puromycin reactions with ribosomal subunits from Artemia salina embryos are present in postribosomal supernatants of Artemia, mouse fibroblasts (L cells), and rat liver, as well as in salt washes of rabbit reticulocyte ribosomes. However, whereas all three supernatant factors, like Escherichia coli IF-2, are sensitive to SH-binding reagents, the reticulocyte factor is not. The rat liver and Artemia factors function indiscriminately with Artemia or rat liver ribosomes, but the Artemia factor and E. coli initiation factor IF-2 are not interchangeable.

Keywords: Artemia salina, embryos, cysts, brine-shrimp eggs, eukaryotic ribosomes

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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