On the mechanism of delayed inhibition of protein synthesis in heme-defecient rabbit reticulocyte lysates.
In the absence of added hemin, protein synthesis in a rabbit reticulocyte lysate declines abruptly (shuts off) after about 5 min at 30 degrees. In these studies we have examined the basis for the lag period preceding shut-off. The initiation factor that binds Met-tRNAf, previously shown to be rate-limiting in inhibited, heme-deficient lysates, is found to be used stoichiometrically in the presence of excess inhibitor. We suggest that a principal effect of the inhibitor is to impair the recycling of the Met-tRNAf-binding factor; the lag period is attributable largely to the presence of a pool of excess Met-tRNAf-binding factor, which, once used in initiation, cannot be recycled because of the action of the inhibitor.
D000818:Animals; D002474:Cell-Free System; D004486:Edeine / Q000494:pharmacology; D005914:Globins / Q000096:biosynthesis*; D006418:Heme / Q000172:deficiency*; D007700:Kinetics; D008954:Models, Biological; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects; D010448:Peptide Initiation Factors; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*
D010448:Peptide Initiation Factors; D004486:Edeine; D006418:Heme; D005914:Globins; D012343:RNA, Transfer