The use of [14C]eukaryotic initiation factor 2 to measure the endogenous pool size of eukaryotic initiation factor 2 in rabbit reticulocyte lysate.
[14C]Eukaryotic initiation factor 2 (eIF-2), obtained by reductive methylation of the purified initiation factor, was shown to be active in the unfractionated reticulocyte lysate. This allowed a direct measurement of the endogenous pool size of eIF-2 in rabbit reticulocyte lysate according to the principle of isotope dilution. A value of 20 to 30 pmol/ml of lysate was obtained. Although translational inhibition resulting from hemin deficiency appears to be characterized by a change from catalytic to stoichiometric utilization of eIF-2, the pool size of eIF-2 is too small to account for the normal period of protein synthesis before the onset of translation inhibition. This suggests, therefore, that additional events to eIF-2 alpha phosphorylation may be required for translational inhibition.
D000818:Animals; D007700:Kinetics; D008715:Methionine; D008970:Molecular Weight; D010448:Peptide Initiation Factors / Q000097:blood*; D014176:Protein Biosynthesis; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism
D010448:Peptide Initiation Factors; D012346:RNA, Transfer, Amino Acyl; D008715:Methionine