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36 Cards in this Set

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3 important molecules that are crossroads in lipid/carb metabolism:
-Glucose 6 phosphate
-AcCoA
-Pyruvate
5 main enzymes under allosteric control:
Glycolysis: PFK1, FBPase
FA Biosnth: AcCoA Carboxylase
Pyruvate: PDH
Pyruvate: Pyruvate Carboxylase
Allosteric effectors of PFK1:
Negative: Citrate (sends G6P to gluconeogenesis instead)
Negative: ATP

Positive: F26BP
Allosteric effectors of FBPase1:
Negative: F26BP

Positive: ATP
Result of active PFK1:
Glycolysis
Result of active FBPase1:
Gluconeogenesis
Allosteric effectors of AcCoA Carboxylase:
Positive: Citrate
Allosteric effector PRODUCED BY AcCoA Carboxylase:
Malonyl CoA
Effect of Malonyl CoA
Inhibits CPT1 - turns off FA b-oxidation
Allosteric effectors of PDH:
-Neg Feedback of NADH, AcCoA
NADH inhibits:
-PDH
-TCA Isocitrate dehydrogenase
-TCA Aketoglutarate dehydrogense
Allosteric effectors of Pyruvate Carboxylase
AcCoA Activates it
(as PDH is turned off AcCoA shuttles into gluconeogenesis)
What allows Covalent regulation?
Glucagon:insulin ratio
Glucagon phosphorylation will ACTIVATE 3 things:
-Glycogen phosphorylase (use glycogen stores)
-FBPase2 (turn off glycolysis)
-Hormone sensitive Lipase (HSL)
(turn on
Glucagon phosphorylation will INACTIVATE 3 things:
-Glycogen synthase
-PFK2
-Pyruvate kinase
AMPK
special phosphorylator for AcCoA Carboxylase
What activates AMPK
AMP
What is the effect of AMPK:
Phosphorylation = inactive AcCoA Carboxylase -> no FA biosynth
Molecule that counteracts the effect of AMPK to some degree:
Citrate - if it's building up from TCA, will shuttle to cytosol and allow FA biosynth in spite of high AMP levels.
Covalent regulation of PDH
-Personal phosphorylator
-Inactivates E1
What activates the phosphorylator of PDH?
-AcCoA
-NADH
-ATP
So the effect of High energy on Pyruvate pools:
1. Kinase phosphorylates PDH (-)
2. Pyruvate not used by TCA
3. Shuttle to gluconeogenesis
Effect of LOW energy on pyruvate pools:
1. Kinase inactive; PDH +
2. TCA works
Long term Regulation of gluconeogenesis:
PEPCK gene
How is PEPCK gene regulated?
-Responds to binding elements (Ins/Cort/Epi/cAMP)
-Changes concentration of enzyme
What allows for coordinated regulation of many pathway enzymes at once?
SRE - serum response element
4 enzymes controlled by SRE for FA biosynthesis:
1. ATP-Citrate Lyase
2. Malic enzyme
3. AcCoA Carboxylase
4. FAS (FA Synthase)
2 reactions of TCA shut off by NADH:
(what else turns them off?)
1. Isocitrate Dehydrog
2. a-Ketoglutarate Dehydrog

(Incr ATP/ADP turns off too)
3 Pathways in Cytosol:
1. Glycolysis
2. FA Biosynth
3. PPP
4 Pathways in Mitochondria
1. FA oxidation
2. TCA
3. Oxidative phosphorylation
4. Ketone formation
2 Pathways that interplay between mito and cyto:
1. Gluconeogenesis
2. Urea synthesis
How AcCoA pool converts from TCA to gluconeogenesis:
AcCoA activates Pyruvate Carboxylase
What does Pyruvate Carboxylase do?
AcCoA -> Oxaloacetate that gets sent to cytosol for gluconeogenesis or ketogenesis.
What molecule is specific for adipocytes and involved in Fat mobilization?
HSL - hormone sensitive lipase
What activates HSL?
Glucagon/cAMP/PKA phosphorylation
What is the effect of insulin on HSL?
Inactive - if you're fed you don't need to be using your fat stores.