PPS Flashcards
exam 2
Why is the PPS considered a shunt?
because it starts with a glycolytic intermediate and can end with the production of other glycolytic intermediates
Which is the glyloclytic that the PPS starts with?
Glucose-6-P
PPS has (2) important products
(1) ribose 5 phosphate
(2) NADPH
Why is Ribose 5- phosphate important?
it is needed for nucleotide synthesis
Why is NADPH important?
It is needed:
Synthesis:
- fatty acid synthesis
- cholesterol synthesis
- neurotrasnmitter syntheis
- nucleotide synthesis
Detoxification:
- reduction of oxidized glutathione
- cytochrome p450 monoxygenses
PPS has two stage
- Oxidation
2. Non-oxidation
in the second, non-oxidative phase pentoses are
interconverted
transketolase trasnfers 2 carbon units using
thiamine
the first commited step that is rate-limiting
Glucose 6- DH
Glucose 6- DH inducible by
insulin
Glucose 6- DH inhibited by
NADPH in allosteric feedback inhibition
Glucose 6- DH inhibited by
NADPH in allosteric feedback inhibition
coenzyme of G-6-DH
NADP+
NADPH is involved in
protection from oxidative damage
Which is the most reactive oxygen species? A. Hydrogen peroxide B. Hydroxyl radical C. Hypochlorous Acid D. Oxygen E. Superoxide
B. Hydroxyl radical
Rxn. of O2 with iron can generate
superoxide
NADPH is a source of
superoxide
what is required ofr reduction of peroxides by peroxidase
glutathione
Glutathione
responsible for maintaining the intracellular environment in a reduced state so that disulfide bonds in proteins stay reduced
Heinz bodies
G6PDG deficiency
why do Heinz bodies form?
when RBC are exposed to an oxidizing chemical in vitro
G6P DH uses ___ and creates _____
uses Mg2+ and created NADPH
6-phosphogluconate DH uses ____ and created
uses Mg2+ and created NADPH
used in biological reduction
NADP
