Pentose Phosphate Shunt Flashcards Preview

MCP > Pentose Phosphate Shunt > Flashcards

Flashcards in Pentose Phosphate Shunt Deck (78)
Loading flashcards...
1

where are the enzymes for the pentose phosphate shunt found

in the cytosol

2

important products of the pentose phosphate shunt?

NADPH and ribose-5-phosphate (R5P)

3

The first three steps are referred to as the ___ phase

oxidative

4

oxidative phase

G6P is converted to what? what is released

G6P converted to Ru5_

Co2 is released

5

what is formed during the oxidative phase per glucose

6 NADPH are formed

3 co2 is released

3 Ru5P

6

enzymes invovled in the oxidative phase (G6P-->Ru5P)

two dehydrogenases and lactose

7

phase after the oxidaitive phase?

 nonoxidative phase

8

 nonoxidative phase

converts Ru5P to 

 intermediates of the glycolytic pathway

 

Ru5P → 2 F6P + 1 GAP

9

isomerase, epimerase, transketolase, and transaldolase

are all invovled in 

non oxidative phase

Ru5P → 2 F6P + 1 GAP

10

nonoxidative phase

the enzyme ___ has TPP as a prosthetic group for transferring C2 groups

transketolase

11

how many Co2 does the oxidative phase yeild?

 

glucose has 18 carbons = three CO2 (3 carbons), three Ru5P (15 carbons), and six NADPH

12

how many Ru5P does the oxidative phase yeidl?

3 Ru5P

 

glucose has 18 carbons = three CO2 (3 carbons), three Ru5P (15 carbons), and six NADPH

13

how many nadph does the oxidative phase yield?

6 nadph

 

glucose has 18 carbons = three CO2 (3 carbons), three Ru5P (15 carbons), and six NADPH

14

In the nonoxidative phase, we use the three Ru5P to make___ before F6P and GAP

 one R5P and two Xu5P

15

 one R5P and two Xu5P from the 3 Ru5P are used to make

 two F6P  and one GAP 

16

from phosphate shunt, you gain 6 nadph at the expense of 

one GAP → three CO2

17

 ___  is used primarily as a reductant,

NADPH

18

NAD+ is used primarily as an ___

oxidant

19

which tissues have pentose phopshate pathways?

20

The main uses of NADPH are in ___ and ___

biosynthesis and detoxification

21

NADPH is used by cytochrome P450  in the
small intestine (and liver) to detoxify ____

xenobiotics

22

In red blood cells, NADPH is needed to detoxify 

reactive oxygen species (ROS)

23

Most common human enzyme deficiency is 

G6PDH Deficiency

24

consequences of G6PDH Deficiency

Favism (Hemolytic anemia) when they take antimalralial drugs (quinine or chloroquine)


Selective advantage where malaria is endemic

25

why does G6PDH Deficiency have an advantage  with malaria?

it’s better to pay the metabolic cost of a faster rate of turnover of RBC’s than to die from malaria

26

If we need ribose but not NADPH, we can 

un the nonoxidative phase of the Shunt in reverse, starting with F6P and GAP and ending with R5P

27

If we need ribose but not NADPH, what do you start with?

starting with F6P and GAP and ending with R5P

28

what do we need ribose for? 

 information storage, energy transfer, oxidation/reduction reactions, and enzyme catalysis 

29

how does the body get both nadph and ribose from the shunt? 

run just the oxidative phase of the Shunt and convert all of the Ru5P produced to R5P

30

Any  ratio other than 2 nadph/ribose can be obtained by 

running the oxidative phase in the forward direction and the nonoxidative phase in either direction.