title: On the mode of action of eucaryotic initiation factor 1.
abstract: A factor isolated from the human tonsillar ribosomal wash specifically stimulated the poly (U)-dependent binding of Phe-tRNA to 40S subunits at low Mg2+ concentration and without any requirement for GTP. The stimulated binding of Phe-tRNA to 40S particles was inhibited in proportion to added deacylated tRNA. The factor was inactivated by N-ethylmaleimide, but in the presence of 40S subunits a considerable protection was observed. 40S subunits, incubated with the factor and isolated by centrifugation, carried significant factor activity. The results imply that the human tonsillar factor, which shows a great functional analogy to the eucaryotic initiation factor 1 from other sources, exerts its effect by an initial interaction with the 40S subunit.
mesh_terms: D005033:Ethylmaleimide / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006801:Humans; D008861:Microsomes / Q000378:metabolism; D014066:Palatine Tonsil / Q000648:ultrastructure; D010445:Peptide Elongation Factors / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000378:metabolism*; D010649:Phenylalanine / Q000378:metabolism; D011072:Poly U / Q000494:pharmacology*; D012343:RNA, Transfer / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D010445:Peptide Elongation Factors; D010448:Peptide Initiation Factors; D011072:Poly U; D010649:Phenylalanine; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D005033:Ethylmaleimide