Purification and properties of the guanine nucleotide exchange factor (GEF) from HeLa cells and its role in the initiation of protein synthesis

Thomas M. Mariano, John Siekierka, Severo Ochoa

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A guanine nucleotide exchange factor (GEF)1 1 The abbreviations used are: eIF-2, eukaryotic initiation factor 2; GEF, GDP exchange factor; HCI, heme-controlled translational inhibitor (an eIF-2α kinase); DAI, double-stranded (ds) RNA-activated translational inhibitor (another eIF-2α kinase); Met-tRNAi, eukaryotic initiator methionyl-tRNA; SDS-PAGE, sodium dodecylsulfate-polyacrylamide gel electrophoresis., catalyzing the exchange of GDP bound to initiation factor eIF-2 for GTP, has been isolated from S3 HeLa cells as the eIF-2·GEF complex and extensively purified by procedures originally developed for purification of GEF from rabbit reticulocytes. The HeLa cell factor resembles rabbit reticulocyte eIF-2·GEF in polypeptide composition, catalytic activity, and inactivation by α-phosphorylated eIF-2.

Original languageEnglish
Pages (from-to)1160-1166
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number3
StatePublished - 13 Feb 1986


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