The cell membrane-shielding function of eicosapentaenoic acid for Escherichia coli against exogenously added hydrogen peroxide

The colony-forming ability of catalase-deficient Escherichia coli mutant genetically modified to produce eicosapentaenoic acid (EPA) showed less decrease than in a control strain producing no EPA, when treated with 0.3 mM hydrogen peroxide (H2O2) under non-growth conditions. H2O2-induced protein carbonylation was enhanced in cells lacking EPA. The amount of fatty acids was decreased more significantly for cells lacking EPA than for those producing EPA. Much lower intracellular concentrations of H2O2 were detected for cells with EPA than those lacking EPA. These results suggest that cellular EPA can directly protect cells against oxidative damage by shielding the entry of exogenously added H2O2.