Reactive oxygen species Flashcards Preview

MCBM > Reactive oxygen species > Flashcards

Flashcards in Reactive oxygen species Deck (22):
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

Not all ROS is bad; its good for:

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