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Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Concentration-dependent inactivation of superoxide dismutase
Biochimica Et Biophysica Acta
|July 24, 1981
Summary
Superoxide dismutase (SOD) inactivation by gamma radiation depends on enzyme concentration. Higher concentrations show partial reversal and altered post-irradiation effects, influenced by catalase and scavengers.
Area of Science:
- Biochemistry
- Radiation Chemistry
- Enzymology
Background:
- Superoxide dismutase (SOD) is crucial for cellular defense against oxidative stress.
- Understanding SOD's radiosensitivity is vital for radiation biology and medicine.
- Bovine erythrocyte SOD was chosen as a model enzyme.
Purpose of the Study:
- To investigate the inactivation yield of bovine erythrocyte SOD under gamma irradiation.
- To determine the influence of enzyme concentration on radiation inactivation.
- To explore post-irradiation effects and the role of protective agents.
Main Methods:
- Co60-gamma irradiation of SOD in air, N2, and N2O-saturated solutions.
- Varying initial enzyme concentrations (micromolar range).
- Assessing inactivation yield, post-irradiation effects, and metal ion loss.
- Utilizing catalase and EDTA as scavengers.
Main Results:
- Inactivation yield increased exponentially with initial enzyme concentration.
- Post-irradiation inactivation occurred in aerated solutions below 10 µM, inhibited by catalase.
- Above 10 µM, inactivation was partially reversed and catalase-independent.
- Catalase and EDTA reduced inactivation by 80% in aerated and N2O solutions.
- Radiation caused loss of copper and zinc, less severe than enzyme activity loss.
Conclusions:
- Enzyme concentration significantly modulates SOD inactivation by gamma radiation.
- Post-irradiation effects and protective mechanisms are concentration-dependent.
- SOD's metal ion content is affected by radiation, but enzyme activity loss is more pronounced.
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