Flashcards in Reactive oxygen species Deck (22)
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1
What are the reaction oxygen species
1. Oxygen =superoxide
2. H2O2= hydrogen peroxide
3. HO= hydroxyl radical
2
What are the reactive nitrogen species
1. NO= nitric oxide
2. ONOO- = peroxynitrite
3. NO2 = nitrogen dioxide
3
What causes the formation of free radicals
1. high pO2
2. aging
3. inflammation
4. reperfusion injury
5. chemicals and radiation
6. smog
4
3 major sources of in vivo ROS production
1. reaction of oxygen with metals
2. by product of electron transport
3. product of enzymatic processes
5
What is the fenton reaction
Ferrous iron + hydrogen peroxide to make ferric iron
6
What is the haber weiss reaction
oxygen + hyrodgen peroxide
7
Most cellular oxidative stress comes from mitochondrial misanagement of ____reduction
oxygen
8
Properties of ROS include:
1. short half life
2. highly reactive with proteins, nucleic acids, lipids resulting in dysfunction/mutation
9
What are some enzymatic reactions that produce ROS
1. xanthine oxidase: produces hydrogen peroxide
2. myeloperoxidase: produces HOCl
3. Nitric Oxide Synthase: Produces nitric oxide
10
What is the most reactive free radical
hydroxyl radical HO-
11
What 2 reactions does the hydroxyl radical react with. What does it result in?
1. hydrogen abstraction
2. addition
Results in:
1. Lipid peroxidation; Calcium influx, DNA strand breaks or formation of 8 hydroxy deoxyguanosine which pairs with thymine instead of cysteine leading to mutation.
2. Protein oxidation and degradation.
12
What are markers of oxidative damage
1. Lipid oxidation: MDA and HNE; compounds that form adducts with proteins: advanced lipoxidation endproducts.
2. Protein oxidation: Nitrotyrosine, chlorotyrosine, methionine sulfoxide
3. DNA oxidation: 8 oxoguanosine
13
ROS and diabetes
ROS react with carbohydrates to make reactive carbonyls that react with proteins and form adducts and cross links: advanced glycation end products or AGEs
14
What are receptors of AGEs:
RAGEs; ligand receptor binding triggers response that inc oxidative stress and mimics chronic inflammation via NFkB
15
What does aldose reductase use up
NADPH; to help reverse the damage done by oxidative stress
16
What is the first line of defense for anti oxidant enzymes
Super oxide disputase:
1. Manganese SOD: mitochondria
2: Copper Zinc SOD: uniquitous
3. Catalase: peroxisomes--> convert to water to neutralize
17
Vitamins A and E are ____soluble vitamins. Vitamin C is ___soluble
lipid (work in membranes); water
18
Hypoxia is ____ oxygen to the body tissues
deficient
19
Anoxia is ____of oxygen in the body tissues
absence
20
Ischemia is ____blood supply to the body tissues; which can lead to hypoxia
deficient
21
Hypoxia generates _____ in which cells respond with induction of _____
ROS; HIF -1 (a transcription factor that reg's genes required for glycolysis, inhibition of PDH, alternate subunits of complex IV
22
