Pentose Phosphate Pathway

Front 1

what is the role of NADPH in metabolism?

Back 1

1)biosynthetic reactions
2)maintains a reducing environment in cells
3) maintenance of cell redox status and viability

Front 2

more NAD+ or NADH in the cell?

Back 2

NAD+ (700/1)
....NADH is used up very fast to make ATP

Front 3

more NADP or NADPH in the cell?

Back 3

NADPH (70/1)
...main job is reducing

Front 4

another name for Pentose Phosphate Pathway

Back 4

Hexose Monophosphate Shunt

Front 5

the business end of NADPH

Back 5

Nicitidimide (if reduced is NADPH if oxidzed is NADP)

Front 6

where does the Pentose Phosphate Pathway occur?

Back 6

in the cytosol

Front 7

where is NADPH used in the body?

Back 7

1)liver for detoxification
2)mammary glands (make lipids)
3)adipose tissues (make lipids)
4)adrenal cortex (makes steroids)

Front 8

where NADPH is specifically required in the adrenal cortex?

Back 8

for the nicrosomal 450 Monoxygenase System

Front 9

What is the IMPORTANT molecule that NADPH keeps reduced??

Back 9

glutathione (GSH)

Front 10

What is Glutathione (GSH)?

Back 10

An antioxidant that reduces PROTEIN DISULFIDES non enzymatically, reduces hydrogen peroxide and organic peroxides

Front 11

what is the enzyme that GLUTATHIONE uses to reduce hydrogen peroxides and peroxides?

Back 11

GLUTATHIONE PEROXIDASE

Front 12

what is the product when Glutathione (GHS) redueces other compounds?

Back 12

GSSG (GLUTATHIONE DISULFIDE)

Front 13

Why is NADPH neccessary for Glutathione (GSH) activity?

Back 13

It reduces Glutathionine Disulfide (GSSG) back to Glutathionine (GSH)

Front 14

how is Pentose Phosphate Pathway involved in biosynthesis?

Back 14

It generates 5-C sugars for nucleotide synthesis

Front 15

2 Stages of Pentose Phosphate pathway in forming new sugars

Back 15

1) G6P is oxidized to Ribulose-5-Phosphate (generates 2 NADPH and CO2)

2) Series of interconversions combine sugars of different carbon lengths to form products that can enter glycolysis

Front 16

The 4 pathways that G6P can take

Back 16

1)glycogen
2)back to glucose in liver and kidney
3)glycolysis
4)Pentose Phosphate Pathway

Front 17

what is generated when G6P is converted to Rubulose 5P?

Back 17

NADPH

Front 18

What is G6P first converted to and by what enzyme?

Back 18

6 Phosphoglucno Lactone
by glucose-6-Phosphate Dehydrogenase

Front 19

which step is the COMMITTED STEP for the Pentose Phosphate Pathway?

Back 19

conversion of G6P to the Lactone (6-Phosphoglucnolactone)

Front 20

what controlls teh committed step of the Pentose Phosphate Pathway?

Back 20

substrate availability of NADP+

Front 21

Second step in Pentose Phosphate? Enzyme Number 2?

Back 21

6-Phosphogluconolactone Hydrolase opens up the lactone ring to yield 6-PHOSPHOGLUCONATE

Front 22

Third step in Pentose Phosphate?
Enzyme number 3?

Back 22

6-PHOSPHOGLUCANATE DEHYDROGENASE produces RUBULOSE 5 Phosphate

Front 23

What is produced when 6-Phosphoglucanate is converted to Rubulose 5 Phosphate?

Back 23

NADPH and CO2

Front 24

Where is a Beta Keto Acid formed in Pentose Phosphate Pathway?

Back 24

in the step where 6-Phosphoglucanate Dehydrogenase converts phosphoglucanate to Ribulose 5 Phosphate

Front 25

What happens then B Keto acid forms?

Back 25

Decarboxylats and releases CO2

Front 26

Will also see B Keto Acid with this enzyme in TCA cycle

Back 26

Isocitrate Dehydrogenase

Front 27

Ribulose 5 Phosphate is in equillibrium with what two other sugars?

Back 27

1) Ribose 5 Phosphate
2) Xylulose 5 Phosphate

Front 28

what converts Ribulose 5 Phosphate to Ribose 5 Phosphate? What intermediate is formed?

Back 28

PHOSPHOPENTOSE ISOMERASE
Enediol intermediate

Front 29

What enzyme converts Ribulose 5 Phosphate to Xylulose 5P?

Back 29

PHOSPHOPENTOSE EPIMERASE

Front 30

How does TRANSKETOLASE work?

Back 30

Moves a 2C Keto fragment from a KETOSE DONAR to and ALDOSE ACCEPTOR

Front 31

What configuration must the sugar be in in order for transketolase to work?

Back 31

L configuration

Front 32

What is the tightly bound cofactor that TRANSKETOLASE requires?

Back 32

THIAMINE PYROPHOSPHATE

Front 33

How does transketolase work?

Back 33

Forms a carbanion = strong nucleophile that attaches the carbonyl C of the 2C fragment transferred

Front 34

What is the role of TRANSALDOLASE?

Back 34

Transfers 3C Keto fragment bwetween a Ketose and an Aldose Acceptor

Front 35

what is the cofactor needed for TRANSALDOLASE?

Back 35

NONE

Front 36

how does TRANSALDOLASE work?

Back 36

contains and active site LYSINE...forms a SCHIFF BASE INTERMEDIATE

Front 37

what is the product after TRANSALDOLASE reaction?

Back 37

Fructose-6-Phosphate

Front 38

2 big reasons cells need NADPH

Back 38

1) Synthesis
2) GSSG reaction

Front 39

oxidative branch of Pentose Phosphate Pathway:

Back 39

converts NADP+ to NADPH

Front 40

non-oxidative branch of Pentose Phosphate Pathway:

Back 40

converts Ribulose 5 Phosphate to glycolytic intermediates so that the carbons are not wasted

Front 41

What happens when NADP+ accumulates?

Back 41

Glucose 6 Phosphate Dehydrogenase acts on it and makes NADPH

Front 42

what types of cells would use Pentose Phosphate Pathway to make nucleotides out of Ribose 5 Phosphate?

Back 42

newborns, tumor cells, heart cells after MI

Front 43

how do cells make Ribose 5 Phosphate?

Back 43

uses reversible non-oxidative branch to convert Fructose 6 Phosphate to Ribose 5 Phosphate

Front 44

which type of cells would reverse the non-oxidative part of Pentose Phosphate Pathway?

Back 44

those with little oxidative stress (don't need NADPH) and little biosynthetic activity...any cell that hasn't accumulated NADP+

Front 45

most comon enzyme abnormalty of PP pathway in the clinical setting?

Back 45

Glucose 6 Phosphate Dehydrogenase Deficiency

Front 46

what type of inheritance does Glucose 6 Phosphate Dehydrogenase display?

Back 46

X linked....affects mosly males

Front 47

what is the clinical presentation of Glucose 6 Phosphate Dehydrogenase?

Back 47

Hemolytic Anemia....RBC cannot repair themselves and just make more G6P....very sensitive to deficiencies where enzymes are unstable

Front 48

what can cause the recognition of Glucose 6 Phosphate Dehydrogenase Deficiency?

Back 48

Oxidative Stress

Front 49

How do drugs induce the moderate disorder of Glucose 6 Phosphate Dehydrogenase disorder?

Back 49

drugs that oxidize GSH to GSSG....NADPH is needed to reduce back to GSH

Front 50

Three drugs that can cause oxidative stress and Glucose 6 Phosphate Dehydrogenase disorder to show up

Back 50

Antibiotics
Antimalarials
Antipyretics

Front 51

where is Glucose 6 Phosphate Dehydrogenase deficiency common?

Back 51

African
Chineese
Medeterranian

Front 52

what is the evolutionary hold of the Glucose 6 Phosphate Dehyrdogenase deficiency?

Back 52

provides resistance to malaria....RBCs in which malaria cannot survive