Lipid Peroxidation

Question 1

What is the first step of lipid peroxidation?

Answer 1

Initiation: formation of ROS (reactive oxygen species)

Question 2

Name 3 ROS (free radicals)

Answer 2

Singlet oxygen (O2•-)
Nitric oxide radical (NO•)
Hydroxyl radical (OH•)

Question 3

What is the second step of Lipid Peroxidation?

Answer 3

Propagation: ROS increases creation of more ROS, causing free radical damage, membrane permeability, DNA damage (nuclear + mitochondrial), create more ROS by lipid peroxidation, oxidation of enzymes

Question 4

What does the termination step of lipid peroxidation rely on?

Answer 4

Antioxidants

Question 5

What is the most important lipid soluble antioxidant in the termination step of lipid peroxidation? What recycles this?

Answer 5

Vit E, Vit C recycles Vit E

Question 6

What is the most important H2O soluble antioxidant in the termination step of lipid peroxidation? What are the its locations?

Answer 6

Superoxide Dismutase (SOD)
Location: Mitochondria (Mn SOD), Cytoplasm (CuZn SOD)

Question 7

What is the function of SOD?

Answer 7

Catalyzes O2• —> H2O2

Question 8

What does detoxification of hydrogen peroxide (H2O2) (Anti-oxidation) require? Where is it located?

Answer 8

Glutathione: glutathione peroxidase (Se), glutathione reductase (B2 = FAD; B3 = NADPH)
Liver + RBCs