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Antioxidants, nature and chemistry

Submitted by Dr. Tamer Fouad, M.D.


Antioxidants are substances that protect other chemicals of the body from damaging oxidation reactions


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  Free radicals
Oxidative mechanisms in carcinogenesis

The catalase enzyme:

This enzyme is a protein enzyme present in most aerobic cells in animal tissues. Catalase is present in all body organs being especially concentrated in the liver & erythrocytes.  The brain, heart, skeletal muscle contains only low amounts.

Catalase and glutathione peroxidase seek out hydrogen peroxide and convert it to water and diatomic oxygen. An increase in the production of SOD without a subsequent elevation of catalase or glutathione peroxidase leads to the accumulation of hydrogen peroxide, which gets converted into the hydroxyl radical. Indeed research in the pathogenesis of Down?s syndrome has revealed that the existence of trisomy 21 leads to the overproduction of SOD, the gene for which is located also on chromosome 21. This finding is intriguing in that it reveals the possibility of a genetic link to the increased activity of free radicals.

                             2 H2O2 ? 2 H2O + O             (Krinsky, 1992)

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