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14 Cards in this Set
- Front
- Back
Aspartate-glutamate transporter & Malate-alpha-ketoglutarate transporter found?
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Inner mitochondrial matrix because it is impermeable to small molecules and maintains membrane potential.
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In what conditions
(anerobic/aerobic) facilitates the conversion of pyruvate to acetyl-coA? |
In aerobic, bc if in anerobic, need some pyruvate in the cytosol to be converted to lactate. Need to maintain NAD/NADH for glycolysis.
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Pyruvate + NAD+ + CoA--->Acetyl-CoA + NADH+ CO2
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This step is irreversible
Pyruvate Dehydrogenase (PDH) |
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ADP, Insulin turn pyruvate metabolism on/off?
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On
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Glucagon turns pyruvate metabolism on/off?
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Off
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The fates of pyruvate
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1. Lactate
2. Alanine for protein synthesis 3. OAA 4. Acetyl CoA a. TCA cycle for ATP b. Steroids c. fat |
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Pyruvate Dehydrogenase (PDH) complex large because?
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1. enhance rate of sequential reactions
2. minimize side reactions 3. stabilize against proteolysis (strengh in numbers) 4. permit coordinated regulation Contains E1, E2 & E3, 5 cofactors |
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Cofactors of PDH
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1. Coenzyme A
2. Thiamine Pyrophosphate (TPP) 3. NAD 4. FAD 5. Lipolic acid |
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Thiamine Pyrophosphate
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Tightly bound to E1
Accepts 2 carbons from pyruvate and transfers them to make Acetyl CoA |
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Lipoic acid/lipoamide
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-Covalently bound to E2
-Hook up with Lysine to get long arm, which reaches from E1, E2, and E3 to accommplish transfer. -Inhibition by arsenic |
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Pyruvate + NAD+ HSCoA -->AcCoA + NADH +CO2 How?
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1. PDH w/ 3 E + Cofactors bound
2. Decarboxylate pyruvate & transfer to TPP (E1) 3. Oxidation of alcohol and transfer to Lipolic acid on E2 4. Lipolic acid transfers 2 Carbons to Acetyl-CoA 5. Now have reduced S groups-must be oxidized on Lipolic acid 6. Transfer H to FAD-->FADH2 on E3 7. Don't want FADH2, but FAD and so therefore transfer H's to NAD--> NADH |
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Negative regulators of PDH
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Direct: Inhibited by pds (Ac.CoA & NADH)
Indirect: Pds (Ac.CoA & NADH) active kinase which phosphorylates PDH--> inactive |
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Positive regulators of PDH
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Direct: Signals of low energy (AMP, GDP)
Indirect: Pyruvate, CoASH, NAD which inhibit kinase-->PDH unphoshorylated-->active |
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Hormonal regulation
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Insulin-high blood sugar activates PDH through phosphatase (unphosphorylate it)
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