EFFECT OF OXIDATIVE STRESS, PRODUCED BY CUMENE HYDROPEROXIDE, ON THE VARIOUS STEPS OF PROTEIN-SYNTHESIS - MODIFICATIONS OF ELONGATION FACTOR-II

We have studied the effect of oxidative stress on protein synthesis in rat liver. Cumene hydroperoxide (CH) was used as an oxidant agent, Th e approach used was to determine the ribosomal state of aggregation an d the time for assembly and release of polypeptide chains in the proce ss of protein synthesis in rat liver in vivo. The results suggest that the elongation step is the most sensitive to CH treatment. The measur ement of both carbonyl groups content and ADP-ribosylatable elongation factor 2 (EF-2), the main protein involved in the elongation step, in dicates that under CH treatment EF-2 is oxidatively modified and a low er amount of active EF-2 is present. These results are corroborated by in vitro oxidation of EF-2 and could explain for the decline in the e longation step.