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29 Cards in this Set

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refresher
Describe all of glycolysis, start with glucose
Glucose->G6P->F6P (note: facilitates GKRP-glucokinase) -> F16P (takes ATP) -> GAP3 and DHAP -> 1,3bisphosphoglycerate (makes NADH)-> 3phosphoglycerate (makes ATP) ->2phosphoglycerate ->phosphoenolpyruvate -> pyruvate (makes ATP) -> lactate (regenerates NAD)
how many ATP/NADH do you get out per glucose in glycolysis
2 ATP total (2 used four made)
2 NADH
regenerate NAD through lactate dehydrogenase, also through TCA cycle(really through malate aspartate shuttle system so get NAD right away)
describe the malate aspartate shuttle

FIRST HALF, getting malate in
NADH transfers electrons to oxaloacetate forming malate

malate crosses into mito via malate/alpha-ketoglutarate antiport

malate gives up electrons to NAD forming oxaloacetate
malate aspartate shuttle

SECOND HALF, getting oxaloacetate out
oxaloacetate is transaminated to aspartate
(this is done through glutamate turning into alpha-ketoglutarate)

aspartate is transported out of the mito via a glutamate/aspartate antiport

aspartate is then change into oxaloacetate (from alphaketoglutarate going to glutamate)

SEE PAGE 27, look i SAY
build up of what inside the mito drives malate inside?
alpha-ketoglutamate
build up of what outside the mito drives aspartate out?
glutamate
how else can you get NADH inside?
glycerol 3-phosphate shuttle
glycerol 3-phosphate shuttle
nadh gives electrons to dihydroxyacetone phosphate (DHAP) making glycerol-3-phosphate

glycerol-3-phosphate hands off electrons to membrane mito deH changing FAD to FADH2 (g3p goes back to DHAP)

FADH2 hands off to Q which can then enter the respiratory chain
how do yeast deal with anaerobic respiration
pyruvate-> acetaldehyde
->ethanol (makes NAD)
what is the commitment step for glycolysis
PFK1
how is PFK 1 negatively regulated
allosteric regulation:
Negative: ATP (binds catalytic site), 3-phosphoglycerate, phosphoenolpyruvate, citrate(muscle), phosphocreatine(muscle), H+, lactate
how is PFK1 positively regulated
AMP
ADP
F6P (binds catalytic)
F2,6P
see page 30 for the effects of substrate concentration (of ATP and F6P each) on the velocity of the PFK reaction
ATP - for ATP: first it rises then it declines, this is because ATP is a subtrate for the reaction, but is also a negative inhibitor

F6P is sigmoidal showing positive cooperativity; the more F6P, the faster the rxn goes
PFK and ATP
atp is a substrate, but it also affects F^P binding and therefore is a neg heterotropic effector
what type of regulation is ATP on PFK reaction (hint: not looking for "negative regulation")
a K-type regulation: substrate binding is affected, not Vmax

has no allosteric effect as a binder of the catalytic site, but is a negative allosteric effector in interfering with F6P
the relaxed state of PFK1 has a high affinity for what?
F6P
F2,6P
AMP
the taut state has a high affinity for what
ATP
Citrate
Describe PFK2, in liver, heart and skeletal muscle, specifically what is phosphorylated
F2,6P is syn'd and degraded by an enz which has both a kinase and phosphatase activity

the kinase activity is PFK2?

Phosphorylation of PFK2 is inhibitory and controlled by PKA (which as we know is regulated by cAMP)

epi in heart stimulates glycolysis

glucagon in liver supresses glycolysis
what does f2,6bP do?
makes PFK1 sensitive to regulation by glucagon
and inhibits F1,6Pase
is the key allosteric regulator of PFK1
PFK2 in liver and heart, what does phosphorylation of this enzyme do in each
hormones->increase cAMP->increases PKA, which phosphorylates PFK2,

P-PFK2 in heart inhibits phosphatase, so kinase is active and F6P goes to F26P which stimulates PFK1 and therefore glycolysis

P-PFK2 in liver has the kinase inhibited so the phosphatase works. this decreases F2,6P so it cant stimulate PFK1 so
liver and heart PFK 1 are mainly effected by F2,6P, what are the rest of tissues positively effected by?
AMP
will high blood sugar increase or decrease F2,6P in the liver? in the heart?
it will increase F2,6P thereby increasing glycolysis in times of plentiful sugar
glucagon->increase cAMP->PKA->p-PFK2(phosphatase active)->low F2,6P and low PFK1 activity

in the heart it is stress that activates PKA, not blood sugar, high stress = increase glycolysis = increase F26P
will stress increase or decrease F2,6P
increase

epi increases cAMP->PKA-> P-PFK2(kinase active)->F26P active

glucagon ->increase cAMP->
MOVING ON
oiuft
PYRUVATE KINASE
positive and negative effectors
in liver it is an allosteric enzyme

positive: F1,6bP
PEP
negative: ATP
See biochem carbs 1 slides 31-38
DO IT
List the four tissue specific isozymes of pyruvate kinase
L- in liver and kidneys
R - in RBC
M1 - heart brain muscle
M2 - all remaining tissues

note: M2 muscarinic receptors in heart
M1/3 muscarinic receptors in all other tissue
muscarinic receptors are found as end organ receptors of parasymp, inhib by atropine
L and R pyruvate kinase isoforms, explain the gene
transcriptional
post transcriptional
tranlational
post translational
TRANSCRIPTIONAL

same gene, different promoters, = different amino termini

L has a tata box - contains serine residue at 11
R has a CAAT box - no serine residue at 11
M1 and M2 explain gene processing
post transcriptional

ALTERNATE SPLICING
RNA editing