Antioxidant enzymes are chemical substances found in plants that acn protect the body from damage of free radicals by terminating the chain reactions by removing free radical intermediates and inhibiting other oxidation reactions.
Catalase is an enzyme, found in most living organisms that are exposed to oxygen helped to converse hydrogen peroxide (free radicals) to water and oxygen as a rate of 40 million molecules of hydrogen peroxide to water and oxygen each second, using either an iron or manganese cofactor.
2. Glutathione peroxidase
The function of glutathione peroxidase is to protect the organism from oxidative damage by reducing lipid hydroperoxides, an oxidation of lipid cell membranes which can easily break and form free radicals of the form RO and converting free hydrogen peroxide to oxygen and water.
3. Glutathione reductase
Glutathione reductase, an enzyme reduces pair of sulfur atoms glutathione to the a organosulfur compound form of antioxidant (consisting of three amino acids joined by peptide bonds) which helps to prevent damage of important cellular components caused by free radicals and peroxides.
4. Super oxide dismutase (both Cu-Zn and Mn)
Super oxide dismutase is an important antioxidant defense in nearly all cells exposed to oxygen by converting superoxide into oxygen and hydrogen peroxide depending on the metal cofactor such as both Cu-Zn and Mn.