Possible accumulation of non-active molecules of catalase and superoxide dismutase in S. cerevisiae cells under hydrogen peroxide induced stress |
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Authors: | Maria M Bayliak Halyna M Semchyshyn Volodymyr I Lushchak |
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Institution: | (1) Department of Biochemistry, Vassyl Stefanyk Precarpathian National University, Ivano-Frankivsk, 76025, Ukraine |
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Abstract: | The effect of hydrogen peroxide on the activities of catalase and superoxide dismutase (SOD) in S. cerevisiae has been studied under different experimental conditions: various H2O2 concentrations, time exposures, yeast cell densities and media for stress induction. The yeast treatment with 0.25–0.50 mM
H2O2 led to an increase in catalase activity by 2–3-fold. At the same time, hydrogen peroxide caused an elevation by 1.6-fold
or no increase in SOD activity dependently on conditions used. This effect was cancelled by cycloheximide, an inhibitor of
protein synthesis in eukaryotes. Weak elevation of catalase and SOD activities in cells treated with 0.25–0.50 mM H2O2 found in this study does not correspond to high level of synthesis of the respective enzyme molecules observed earlier by
others. It is well known that exposure of microorganisms to low sublethal concentrations of hydrogen peroxide leads to the
acquisition of cellular resistance to a subsequent lethal oxidative stress. Hence, it makes possible to suggest that S. cerevisiae cells treated with low sublethal doses of hydrogen peroxide accumulate non-active stress-protectant molecules of catalase
and SOD to survive further lethal oxidant concentrations. |
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Keywords: | Saccharomyces cerevisiae hydrogen peroxide catalase superoxide dismutase |
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