Antioxidants - Goueli Flashcards
When does oxidative stress occur?
When the rate of ROS and RNOS generation exceeds the capacity of the cell for their removal
What removes the superoxide free radical?
Superoxide dismutase (SOD) in mitochondria
What removes hydrogen peroxide and lipid peroxides?
Catalase and glutathione peroxidase
How does superoxide dismutase work?
Converts superoxide anion to hydrogen peroxide and oxygen in a process of dismutation
How does glutahione peroxidase work?
Reactive sulfhydryl groups to reduce hydrogen peroxide to water and lipid peroxides to nontoxic alcohols
What are the actions of nonenzymatic antioxidants (free radical scavengers)?
Convert free radicals to a nonradical, nontoxic form in nonenzymatic reactions
What is the primary defense against oxidative stress and why?
Superoxide dismutase because superoxide is a strong initiator of chain reactions
Superoxide dismutase mutations are associated with what disease?
Familial ALS (5-10% of ALS cases)
How does catalase work?
Protects immune cells from respiratory burst
Hydrogen peroxide must be reduced to ______ to prevent it from forming the _________ _______ in the _______ Reaction or the _______-_______ Reaction.
water
hydroxyl radical
Fenton
Haber-Weiss
Where is catalase found in the cell and in the body?
Cell: Peroxisomes, cytosol, microsomal cell fraction
Body: Kidney, Liver (high peroxisome content)
Where is glutathione peroxidase found in the cell?
Cell: Outside of Peroxisomes, In cytosol and mitochondria
What does vitamin C (ascorbic acid) deficiency cause in terms of symptoms?
Survey
- impaired wound healing
- bleeding ecchymosis
- swollen gums
- anemia
- enlargement and keratosis of hair follicles
- lethargy
- depression
