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. 1978 Jan;75(1):243–247. doi: 10.1073/pnas.75.1.243

Mode of action of the hemin-controlled inhibitor of protein synthesis.

C de Haro, A Datta, S Ochoa
PMCID: PMC411222  PMID: 272639

Abstract

Despite the finding that the hemin-controlled translational inhibitor in reticulocyte lysates is a cyclic AMP-independent protein kinase that phosphorylates the small subunit of the initiation factor eIF-2, the mechanism of inhibition of translation remained unexplained. Whereas treatment of hemin-containing lysates with inhibitor in the presence of ATP inhibited translation, the same treatment of highly purified eIF-2 did not affect its ability to form a ternary complex with initiator Met-tRNA and GTP or a 40S initiation complex. We have isolated from ribosomal salt washes a protein (eIF-2 stimulating protein) that enhances the capacity of unphosphorylated eIF-2 to form ternary or 40S initiation complexes but has no effect on the phosphorylated factor. At low concentrations, eIF-2 is virtually inactive without this stimulating protein. Therefore, the translational inhibitor acts by converting eIF-2 to a form that is not stimulated by the stimulating protein.

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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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