PPP pathway and G6PD deficiency Flashcards Preview

Medical Biochemistry > PPP pathway and G6PD deficiency > Flashcards

Flashcards in PPP pathway and G6PD deficiency Deck (38):
1

what are other names for the pentose phosphate pathway?

hexose monophosphate shunt (HMP shunt) or 6-phosphogluconate pathway

2

where does PPP occur?

cytosol of cells

3

what is PPP and what is it NOT?

its a alternate pathway for metabolism of glucose - doesn't produce ATP or any energy

4

what does the PPP produce?

provides NADPH + H
provides pentoses

5

what is NADPH produced in the oxidative pathway used for?

reductive biosynthetic reactions

6

what are the pentoses used for?

nucleotide synthesis for nucleic acid synthesis RNA and DNA!

7

where is the PPP active? - important

liver
lactating mammary glands
adipose tissue (provides NADPH for fatty acid biosyn)
adrenal cortex
testes/ovaries (NADPH for syn of steroid hormones)
RBCs (NADPH for red. of glutathione)
WBCs and macrophages (NADPH for phagocytosis)

8

what is the regulatory enzyme?

glucose 6-phosphate dehydrogenase

9

what uses TPP as a coenzyme in PPP?

transketolase

10

what can be used to test nutritional thiamine deficiency?

transketolase activity in RBCs

11

what is NADPH used for in the biosynthesis of?

reactions in fatty acid synthesis of steroid hormones
Synthesis of nitric oxide (NO)

12

what does NADPH reduce and detoxify?

hydrogen peroxide

13

what is used in the cytochrome P450 system?

NADPH

14

NADPH is used for phagocytosis in what?

WBCs

15

what produces superoxide free radicals in WBCs?

NADPH oxidase

16

what does deficiency of NADPH oxidase cause?

chronic granulomatousdisease characterized by severe persistent infections
•Infections result in increased production of oxidants

17

what is the major antioxidant in RBCs to detox hydrogen peroxide?

GSH

18

what can PPP defect cause in RBCs?

accumulation of hydrogen peroxide because of no GSH is being produced from NADPH and there for is damages the membrane and causes hemolysis in RBCs

19

what is the most common enzyme abnormality?

G6PD = x linked recessive- then PK

20

what can G6PD deficiency result in?

accumulation of free radials like hydogen peroxide
formation of denatured proteins as insoluble masses = heinz bodies

Hemolytic anemia

21

where does G6PD deficiency occur?

all cells, but more severe in RBC

22

what is the only way RBCs can get NADPH?

PPP

23

what exactly causes a deficiency in G6PD?

oxidative stress
infection
fava beans - Met
oxidant drugs = sulfa drugs - primaquine

24

what cells are especially vulnerable to G6PD deficiency?

old (senile) RBCs - they have no nucleus or ribosomes and cannot synthesize new enzyme

25

what does G6PD A- result in?

moderate form of G6PD deficiency
its a drug induced hemolytic anemia

26

when do patients have hemolytic manifestations? even if the sig. portion of young RBCs with G6PD A- have sufficient levels of the enzyme?

when expoed to one of the precipitating factors = infection, oxidant rug, fava beans

27

what are the precipitating factors(oxidants)?

infection
oxidant drugs = sulfa drugs/antimalarial drugs = primaquine
fava beans

28

in short, what does G6PD deficiency reduce ?

the levels of GSH levels - can't break down oxidants!

29

how is nitric oxide synthesized?

nitric oxide synthase uses NADPH
oxygen
arginine

29

what is Glutathione reductase coenzyme?

NADPH

30

what is coenzyme of glutathione perioxidase?

Selenium

30

what two major pathways in the liver use NADPH for reductive biosynthesis?

fatty acid de-novo synthesis and cholesterol synthesis.

31

what enzymes need NADPH for drug metabolism?

The group of cytochrome P450 needs NADPH.

31

what is coenzyme of glutathione perioxidase?

Selenium

32

what two major pathways in the liver use NADPH for reductive biosynthesis?

fatty acid de-novo synthesis and cholesterol synthesis.

32

what two major pathways in the liver use NADPH for reductive biosynthesis?

fatty acid de-novo synthesis and cholesterol synthesis.

33

what enzymes need NADPH for drug metabolism?

The group of cytochrome P450 needs NADPH.

33

what enzymes need NADPH for drug metabolism?

The group of cytochrome P450 needs NADPH.