title: Functional heterogeneity of GEF-free initiation factor 2 purified from suckling and adult rat brain.
abstract: The functional behavior of initiation factor 2 was studied in purified preparations from the brains of suckling (4-12-day-old) and adult (60-day-old) rats. Adult eIF2 has lower GDP and GTP affinity than suckling eIF2, even in the presence of a large excess of GTP, whereas suckling eIF2 has a lower capacity to bind GTP. Since these two factors are free of guanine nucleotide exchange factor (GEF), and ribosomal fractions show an age-dependent difference in GEF activity, the observed functional heterogeneity may be due to a different ratio in eIF2 species (eIF2-GDP, eIF2(alpha P)).
mesh_terms: D000375:Aging; D000818:Animals; D000833:Animals, Suckling; D001923:Brain Chemistry; D015852:Eukaryotic Initiation Factor-2; D020662:Guanine Nucleotide Exchange Factors; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D010448:Peptide Initiation Factors / Q000302:isolation & purification / Q000502:physiology*; D011506:Proteins / Q000302:isolation & purification / Q000502:physiology*; D051381:Rats
chemical_list: D015852:Eukaryotic Initiation Factor-2; D020662:Guanine Nucleotide Exchange Factors; D010448:Peptide Initiation Factors; D011506:Proteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate