title: Evidence that a single GTP is used in the formation of 80 S initiation complexes.
abstract: Evidence is presented that the GTP initially bound in ternary complex (Met-tRNAf.GTP.eukaryotic initiation factor 2 (eIF-2)) is the same GTP that is hydrolyzed to allow joining of a 40 S preinitiation complex with 60 S subunits. This evidence was obtained by two quite dissimilar techniques. The first was a kinetic analysis of AUG-directed methionyl-puromycin synthesis using either eIF-2 of eIF-2A to direct the binding of Met-tRNAf to 40 S subunits. The second technique was the isolation of 40 S preinitiation complexes by Sepharose 6B chromatography and subsequent quantitation of GTP hydrolysis and methionyl-puromycin synthesis under conditions where 80 S complex formation is permitted.
mesh_terms: D000818:Animals; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D008715:Methionine; D010442:Peptide Chain Initiation, Translational; D010448:Peptide Initiation Factors / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism
chemical_list: D010448:Peptide Initiation Factors; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D008715:Methionine