title: Fractionation and partial characterization of the protein synthesis system of wheat germ. I. Resolution of two elongation factors and five initiation factors.
abstract: Wheat germ S100 supernatant was resolved into 10 components, all of which are required for tobacco mosaic virus RNA-directed incorporation of amino acid into protein. Two of the components, C2b and C2a, are, respectively, elongation factors 1 and 2, having molecular weights of 51,000 and 72,000. A third factor (C2e) binds Met-tRNA in a GTP-requiring reaction and is absolutely required for the formation of both 40 S ribosome.Met-tRNAiMet and 80 S ribosome.Met-tRNAiMet complexes. This factor is considered to be eucaryotic initiation factor 2. Formation of 80 S ribosome Met-tRNAiMet complexes is augmented 2 to 3-fold by the simultaneous addition of an mRNA, factor C1, and fraction D2(a + b). Factor C1 also reverses the inhibition of translation by an increased concentration of monovalent cations and promotes the translation of a "competitively inhibited" mRNA. These observations suggest that factor C1 and either factor D2a and D2b (or both) function in mRNA attachment reactions. Factor C1 has a molecular weight of 115,000 and appears to be made up of two or three subunits. Factor D2b has been purified to essential homogeneity and has a molecular weight of 55,000. Its interaction with mRNA and its molecular weight suggest that this factor is the wheat germ equivalent of reticulocyte eucaryotic initiation factor 4A.
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D015977:Eukaryotic Initiation Factor-1; D015852:Eukaryotic Initiation Factor-2; D008970:Molecular Weight; D010445:Peptide Elongation Factors / Q000302:isolation & purification*; D010448:Peptide Initiation Factors / Q000302:isolation & purification*; D011108:Polymers; D014176:Protein Biosynthesis; D011506:Proteins / Q000302:isolation & purification; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism
chemical_list: D000596:Amino Acids; D015977:Eukaryotic Initiation Factor-1; D015852:Eukaryotic Initiation Factor-2; D010445:Peptide Elongation Factors; D010448:Peptide Initiation Factors; D011108:Polymers; D011506:Proteins; D012346:RNA, Transfer, Amino Acyl; C026464:tRNA(m)(Met), methionine-