PPP pathway and G6PD deficiency

Question 1

what are other names for the pentose phosphate pathway?

Answer 1

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

Question 2

where does PPP occur?

Answer 2

cytosol of cells

Question 3

what is PPP and what is it NOT?

Answer 3

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

Question 4

what does the PPP produce?

Answer 4

provides NADPH + H

provides pentoses

Question 5

what is NADPH produced in the oxidative pathway used for?

Answer 5

reductive biosynthetic reactions

Question 6

what are the pentoses used for?

Answer 6

nucleotide synthesis for nucleic acid synthesis RNA and DNA!

Question 7

where is the PPP active? - important

Answer 7

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)

Question 8

what is the regulatory enzyme?

Answer 8

glucose 6-phosphate dehydrogenase

Question 9

what uses TPP as a coenzyme in PPP?

Answer 9

transketolase

Question 10

what can be used to test nutritional thiamine deficiency?

Answer 10

transketolase activity in RBCs

Question 11

what is NADPH used for in the biosynthesis of?

Answer 11

reactions in fatty acid synthesis of steroid hormones

Synthesis of nitric oxide (NO)

Question 12

what does NADPH reduce and detoxify?

Answer 12

hydrogen peroxide

Question 13

what is used in the cytochrome P450 system?

Answer 13

NADPH

Question 14

NADPH is used for phagocytosis in what?

Answer 14

WBCs

Question 15

what produces superoxide free radicals in WBCs?

Answer 15

NADPH oxidase

Question 16

what does deficiency of NADPH oxidase cause?

Answer 16

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

Question 17

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

Answer 17

GSH

Question 18

what can PPP defect cause in RBCs?

Answer 18

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

Question 19

what is the most common enzyme abnormality?

Answer 19

G6PD = x linked recessive- then PK

Question 20

what can G6PD deficiency result in?

Answer 20

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

Hemolytic anemia

Question 21

where does G6PD deficiency occur?

Answer 21

all cells, but more severe in RBC

Question 22

what is the only way RBCs can get NADPH?

Answer 22

PPP

Question 23

what exactly causes a deficiency in G6PD?

Answer 23

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

Question 24

what cells are especially vulnerable to G6PD deficiency?

Answer 24

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

Question 25

what does G6PD A- result in?

Answer 25

moderate form of G6PD deficiency | its a drug induced hemolytic anemia

Question 26

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

Answer 26

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

Question 27

what are the precipitating factors(oxidants)?

Answer 27

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

Question 28

in short, what does G6PD deficiency reduce ?

Answer 28

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

Question 29

how is nitric oxide synthesized?

Answer 29

nitric oxide synthase uses NADPH oxygen arginine

Question 29

what is Glutathione reductase coenzyme?

Answer 29

NADPH

Question 30

what is coenzyme of glutathione perioxidase?

Answer 30

Selenium

Question 30

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

Answer 30

fatty acid de-novo synthesis and cholesterol synthesis.

Question 31

what enzymes need NADPH for drug metabolism?

Answer 31

The group of cytochrome P450 needs NADPH.

Question 31

what is coenzyme of glutathione perioxidase?

Answer 31

Selenium

Question 32

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

Answer 32

fatty acid de-novo synthesis and cholesterol synthesis.

Question 32

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

Answer 32

fatty acid de-novo synthesis and cholesterol synthesis.

Question 33

what enzymes need NADPH for drug metabolism?

Answer 33

The group of cytochrome P450 needs NADPH.

Question 33

what enzymes need NADPH for drug metabolism?

Answer 33

The group of cytochrome P450 needs NADPH.