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Ascorbic acid and oxidative inactivation of proteins.
1Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
The American Journal of Clinical Nutrition
|December 1, 1991
Summary
Ascorbate (Vitamin C) protects cells from oxidative damage but can paradoxically generate harmful reactive oxygen species in the presence of certain metal ions, contributing to disease.
Area of Science:
- Biochemistry
- Cell Biology
- Pathology
Background:
- Reactive oxygen species (ROS) are implicated in aging and diseases like arthritis and cancer.
- Ascorbate (Vitamin C) is crucial for cellular protection against oxidative stress.
Purpose of the Study:
- To investigate the dual role of ascorbate in managing oxidative damage.
- To understand the paradoxical pro-oxidant activity of ascorbate in the presence of transition metals.
Main Methods:
- Investigated the redox reactions between ascorbate and metal ions (Fe3+, Cu2+).
- Examined the generation of reactive oxygen species (ROS) under these conditions.
- Assessed the resulting damage to nucleic acids and proteins.
Main Results:
- Ascorbate reduces Fe3+/Cu2+ to Fe2+/Cu+ and oxygen to superoxide and hydrogen peroxide.
- Metal-ascorbate complexes catalyze ROS production, including hydroxyl radicals.
- This leads to oxidative damage of DNA and proteins at metal-binding sites.
Conclusions:
- Ascorbate's pro-oxidant activity, mediated by transition metals, can contribute to cellular damage.
- Understanding this duality is critical for managing diseases linked to oxidative stress.