Reactive oxygen species

Question 1

What are the reaction oxygen species

Answer 1

1. Oxygen =superoxide
2. H2O2= hydrogen peroxide
3. HO= hydroxyl radical

Question 2

What are the reactive nitrogen species

Answer 2

1. NO= nitric oxide
2. ONOO- = peroxynitrite
3. NO2 = nitrogen dioxide

Question 3

What causes the formation of free radicals

Answer 3

1. high pO2
2. aging
3. inflammation
4. reperfusion injury
5. chemicals and radiation
6. smog

Question 4

3 major sources of in vivo ROS production

Answer 4

1. reaction of oxygen with metals
2. by product of electron transport
3. product of enzymatic processes

Question 5

What is the fenton reaction

Answer 5

Ferrous iron + hydrogen peroxide to make ferric iron

Question 6

What is the haber weiss reaction

Answer 6

oxygen + hyrodgen peroxide

Question 7

Most cellular oxidative stress comes from mitochondrial misanagement of ____reduction

Answer 7

oxygen

Question 8

Properties of ROS include:

Answer 8

1. short half life

2. highly reactive with proteins, nucleic acids, lipids resulting in dysfunction/mutation

Question 9

What are some enzymatic reactions that produce ROS

Answer 9

1. xanthine oxidase: produces hydrogen peroxide
2. myeloperoxidase: produces HOCl
3. Nitric Oxide Synthase: Produces nitric oxide

Question 10

What is the most reactive free radical

Answer 10

hydroxyl radical HO-

Question 11

What 2 reactions does the hydroxyl radical react with. What does it result in?

Answer 11

1. hydrogen abstraction
2. addition
   Results in:
3. Lipid peroxidation; Calcium influx, DNA strand breaks or formation of 8 hydroxy deoxyguanosine which pairs with thymine instead of cysteine leading to mutation.
4. Protein oxidation and degradation.

Question 12

What are markers of oxidative damage

Answer 12

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

Question 13

ROS and diabetes

Answer 13

ROS react with carbohydrates to make reactive carbonyls that react with proteins and form adducts and cross links: advanced glycation end products or AGEs

Question 14

What are receptors of AGEs:

Answer 14

RAGEs; ligand receptor binding triggers response that inc oxidative stress and mimics chronic inflammation via NFkB

Question 15

What does aldose reductase use up

Answer 15

NADPH; to help reverse the damage done by oxidative stress

Question 16

What is the first line of defense for anti oxidant enzymes

Answer 16

Super oxide disputase:

1. Manganese SOD: mitochondria
   2: Copper Zinc SOD: uniquitous
2. Catalase: peroxisomes–> convert to water to neutralize

Question 17

Vitamins A and E are ____soluble vitamins. Vitamin C is ___soluble

Answer 17

lipid (work in membranes); water

Question 18

Hypoxia is ____ oxygen to the body tissues

Answer 18

deficient

Question 19

Anoxia is ____of oxygen in the body tissues

Answer 19

absence

Question 20

Ischemia is ____blood supply to the body tissues; which can lead to hypoxia

Answer 20

deficient

Question 21

Hypoxia generates _____ in which cells respond with induction of _____

Answer 21

ROS; HIF -1 (a transcription factor that reg’s genes required for glycolysis, inhibition of PDH, alternate subunits of complex IV

Question 22

Not all ROS is bad; its good for:

Answer 22

1. respiratory burst
2. nitric oxide (vasodilates)
3. hydrogen peroxide signaling (growth factor signaling for cell growth)