E2 Pentose Phosphate Pathway Flashcards
What is the location of PPP?
cytosol/cytoplasm
What is the main product of PPP?
NADPH
What are the 3 other names for PPP?
A. hexose monophosphate pathway
B. hexose monophosphate shunt
C. phosphogluconate pathway
Name the two phases of PPP.
- oxidative
2. non-oxidative
What is the key regulatory enzyme of PPP?
G-6-P DH
T/F. ATP can be either created or consumed in PPP.
False; no ATP used/made
Which PPP phase includes the interconversion of sugars?
non-oxidative
Which PPP phase includes the production of NADPH?
oxidative
In which cells does the PPP occur?
practically all
Which enzyme(s) phosphorylate glucose?
hexokinase/glucokinase
What cellular condition stimulates PPP?
low NADPH
What is the main sugar in the non-oxidative phase of PPP?
Ribose-5-P
Match the enzyme to the rxn.
A. G-6-P+NADP++H2O –> 6phosphoglucono-sigma-lactone
B. 6phosphoglucono-sigma-lactone –> 6-phosphogluconate
C. 6 phosphogluconate+NADP+ –> Ribose-5-phosphate + NADPH
- lactonase
- 6-phosphogluconate DH
- transketolase
- glucose-6-phosphate DH
- transaldolase
A. 4
B. 1
C. 2
Which rxn is the key rate limiting step in PPP? Is it reversible?
G-6-P + NADP+ + H2O –> 6 phosphoglucono-sigma-lactone; none are reversible
How many NADPH are produced per 1 glucose-6-phosphate?
2
What is used as an electron donor in detoxification?
NADPH
Which rxn does NADPH not provide reducing power for? (pick two) A. cholesterol synthesis B. nucleotide synthesis C. protein synthesis D. respiratory bursts E. antioxidant regeneration F. fatty acid synthesis G. fatty acid breakdown H. detoxification
C. protein synthesis
G. protein breakdown
Which detoxification system is used in the liver?
P450 monooxygenase system and/or cytochrome 450 monooxygenase system
_____ and _____ are required to make toxins soluble.
Electrons, oxygen
Name the process in which white blood cells take in more oxygen.
respiratory burst
What is the location of the cytochrome P-450 monooxygenase system?
endoplasmic reticulum
What is the fate of soluble toxins?
excrete in urine
Where are reactive molecules and non-self (bacteria) sequestered?
in a vesicle
In a respiratory burst, is NADPH used as an electron donor or acceptor?
donor
What is used to produce reactive molecules in harsh chemistry?
O2 and electrons from NADPH
Respiratory Burst Matching
A. O2+NADPH –> O2- +NADP+
B. O2- –> H2O2
C. H2O2 –> HClO
- lactonase
- superoxide dismutase
- transketolase
- myeloperoxide
- oxidase
- G-6-P DH
A. 5
B. 2
C. 4
What is the lettering for hypochlorous acid? Superoxide?
HClO, O2-
_______ give electrons to free radicals to “quench” them.
antioxidants
Proteins, phospholipids, and DNA are oxidized via _______.
free radicals
_______ gives electrons to antioxidants.
NADPH
Do free radicals have paired or unpaired electrons? Do they want to give or take electrons?
unpaired, take electrons
Antioxidants Matching (multiple answers for each)
A. superoxide
B. hydrogen peroxide
- reactive species
- free radical
- catalase
- O2-
- glutathione peroxide
- superoxide dismutase
A. 2, 4, 6
B. 1, 3, 5
What are the 3 cofactors of superoxide dismutase?
zinc, copper, manganese
What is the cofactor of catalase?
iron
What is the cofactor of glutathione peroxide (GPX)?
selenium
Name the location(s) of superoxide dismutase.
extracellular, cytoplasm, mitochondria
What is the major location of catalase?
cell peroxisomes
Name the location(s) of GPX.
cytosol, mitochondria
What are the 2 functions of superoxide dismutase?
- eliminate superoxide
2. produce H2O2
What is the main function of catalase and GPX?
eliminate H2O2
T/F. Neutrophils have LOTS of catalase.
true
What is the most significant antioxidant in the elimination of H2O2?
GPX
What makes up the tripeptide glutathione?
glutamate-cysteine-glycine
Glutathione Matching
A. GSH
B. GSSG
- oxidized form
- reduced form
A. 2
B. 1
Regerating glutathione requires electrons from ______.
NADPH
What is the enzyme that facilitates GSSG —> 2-GSH?
glutathione reductase
What enzyme facilitates O2- —> H2O?
superoxide dismutase
What enzyme facilitates H2O —> H2O + O2?
catalase
What enzymes facilitates H2O —> H2O?
GPX
T/F. When antioxidants are regenerated, PPP is inhibited.
false; stimulates PPP
Pentose Phosphate Pathway is ______ driven.
product
Matching
A. Ribose-5-Phosphate (C5)
B. Glyceraldehyde-3-phosphate
- transketolase
- transaldolase
A. 1
B. 2
T/F. Ribose is NOT needed for DNA and RNA.
False
What are options for reversible non-oxidative reactions?
build new cells, glycolysis, recycle sugars to G-6-P
