EF-1alpha is a target site for inhibitory effect of quercetin in the peptide elongation process

The effect of quercetin (3,3',4',5,7-pentahydroxyflavone) on the polypeptide elon­gation system isolated from rat liver cells, was investigated. Quercetin inhibited [ 4C]leucine incorporation into proteins in vitro and the inhibitory effect is being directed towards the elongation factor eEF-1, but not to eEF-2 and ribosomes. Quer­cetin was found to form a complex with EF-la, which was inactive in GTP-dependent binding to ribosomes. It can be suggested that quercetin can block the total or the part of the domain of EF-la structure that is responsible for formation of the ternary complex EF-la-GTP-i14C]Phe-tRNA and therefore preventing formation of the quater­nary complex with ribosomes.