title: Stimulation and inhibition of the protein synthetic process by NAD+ in lysed rabbit reticulocytes.
abstract: NAD+ at 0.16 mM stimulates the initiation step of the protein synthetic process in lysed rabbit reticulocytes. This conclusion is based on the stimulation of (i) the transfer of formylmethionine from f[35S]Met-tRNAfMet into polypeptide, (ii) the accumulation of the initial dipeptide, methionylvaline, in the presence of pactamycin, and (iii) the formation of the 40 S initiation complex. The effect of NAD+ changes from a stimulatory role on protein synthesis to an inhibitory role at concentrations greater than 0.16 mM. At 4.0 mM NAD+, protein synthesis is inhibited. This has been demonstrated experimentally by using the same three assays described above. In addition, 4.0 mM NAD+ inhibits MettRNAfMet.initiation factor.GTP ternary complex formation. The elongation and termination steps of polypeptide synthesis are not affected by 0.16 to 4.0 mM NAD+. The data presented clearly show that the stimulatory activity of 0.16 mM NAD+ and the inhibitory activity of 4.0 mM NAD+ affects the initiation step of the protein synthetic process in lysed rabbit reticulocytes.
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis*; D007700:Kinetics; D008715:Methionine; D009243:NAD / Q000494:pharmacology*; D010452:Peptide Biosynthesis; D010442:Peptide Chain Initiation, Translational / Q000187:drug effects*; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism*
chemical_list: D001798:Blood Proteins; D009243:NAD; D012343:RNA, Transfer; D008715:Methionine