Semchyshyn G. Biochemical peculiarities of antioxidant systems of Escherichia coli strains with different sensitivity to oxygen

Escherichia coli. The effect of environmental factors on activity of antioxidant enzymes and level of oxidized proteins and lipids in E. coli was studied. Increase of oxygen level caused the elevation of some enzyme activity. For the first time it shown that hydrogen peroxide induced enzymes of SoxRS regulon. The scheme of regulation of E. coli SoxRS, OxyR, RpoS regulons was suggested. It based on analysis of literature and present data. Hydrogen peroxide increased the level of oxidized proteins and lipids in E. coli. The values of these parameters depend on mode of stress induction. The method of assay of catalase activity in native cell of E. coli was proposed. Partly desintegrated bacteria demonstrate two catalase peacks: at pH 7,0 - the sum of activities of two known catalase forms of E. coli, and at pH 3,5. The great lability of the last one made impossible its detail analysis.