"In vitro" effect of cumene hydroperoxide on hepatic elongation factor-2 and its protection by melatonin

We have examined by immunoblotting the effect of three oxidant compounds on the level of hepatic elongation factor-2 (eEF-2). Rat liver homogenates were exposed to cumene hydroperoxide (CH), 2-2'-azobis (2-aminopropane) dihydrochloride (AAPH) and H(2)O(2). Only CH treatment produced the disappearance of eEF-2, probably due to a phenomena of peptide bond cleavage. The direct implication of free radical species in this process is evident because of the fact that the inclusion of a free radical scavenger such as melatonin prevented the eEF-2 depletion. The results also suggest that the disappearance of eEF-2 induced by CH can be linked to a lipid peroxidant process, which could account for the decline of protein synthesis in aging and other circumstances where lipid peroxidation is high.