title: Purification of a novel heat-stable translational inhibitor from rabbit reticulocyte lysates.
abstract: We have purified to apparent homogeneity a novel heat-stable (HS) factor from postribosomal supernatants of rabbit reticulocyte lysates by heating for 10 min at 80 degrees C, fractionation on Sephadex, anion-exchange chromatography on QMA Accell, and gel filtration HPLC. The apparent molecular mass of HS is 500-1000 Da on the basis of its behaviour on gel filtration. Like a factor from bovine heart [(1982) Proc. Natl. Acad. Sci. USA 79, 3134-3137], the reticulocyte HS inhibits translation in hemin-supplemented lysates with biphasic kinetics similar to hemin deficiency and promotes phosphorylation of the alpha-subunit of the eukaryotic initiation factor eIF-2. It is active at nanomolar concentrations. Reticulocyte HS appears to be neither a peptide nor an oligonucleotide since HS activity was insensitive to proteolytic or nucleolytic digestion.
authors.affiliation: Centro de Biología Molecular, Universidad Autónoma, Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Gaitero
authors.forename: G G
authors.initials: GG
authors.lastname: Limas
authors.forename: E
authors.initials: E
authors.lastname: Mendez
authors.forename: C
authors.initials: C
authors.lastname: de Haro
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D015852:Eukaryotic Initiation Factor-2; D006427:Hemin / Q000494:pharmacology; D006358:Hot Temperature; D008970:Molecular Weight; D010448:Peptide Initiation Factors / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000302:isolation & purification*; D011506:Proteins / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000032:analysis*
chemical_list: D015852:Eukaryotic Initiation Factor-2; D010448:Peptide Initiation Factors; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D006427:Hemin; D011494:Protein Kinases