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27 Cards in this Set
- Front
- Back
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What does TCA recover energy from? |
Carbs, Fatty acids, amino acids. They are all broken down into acetyl-CoA. |
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Parts of PDH |
Pyruvate Dehydrogenase, Dihydrolipoyl transacetylase, and Dihydrolipoyl dehydrogenase |
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Coenzymes for PDH |
TPP (B1), Lipoamide, CoASH (B5), FAD (B2), and NAD+ (B3) |
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PDH inhibition by high concentrations of |
High Acetyl CoA, High NADH/NAD+, High ATP |
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PDH activation by high concentrations of |
AMP/ADP, Ca+2/Mg+2, Insulin |
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Facts about TCA |
Aerobic Respiration, occurs in mitochondria, oxaloacetates are regenerated, intermediates are precursors |
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Product of TCA |
3 NADH, 1 FADH2, 1 ATP, 2 CO2 |
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Reaction 1 |
Substrates: Oxaloacetate and Acetyl CoA Products: Citrate Enzyme: Citrate Synthase |
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Reaction 2 |
Substrate: Citrate Product: Isocitrate Enzyme: Aconitase |
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Reaction 3 |
Substrate: Isocitrate, then Oxalosuccinate Product: Alpha-ketoglutarate Enzyme: Isocitrate dehydrogenase Note: Yields 1 NADH, 1 CO2. Transient oxalosuccinate. |
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Reaction 4 |
Substrate: Alpha-ketoglutarate Product: Succinyl-CoA Enzyme: Alpha-ketoglutarate dehydrogenase Note: Yields 1 NADH, 1 CO2. A-kg is similar to PDH in structure, mechanism of action, regulation |
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Reaction 5 |
Substrate: Succinyl-CoA Product: Succinate Enzyme: Succinyl-CoA synthetase GTP converter: Nucleoside diphosphate kinase Note: GTP is produced, which is immediately converted into ATP by GTP converter enzyme. |
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Reaction 6 |
Substrate: Succinate Product: Fumarate Enzyme: Succinate dehydrogenase Coenzyme: B2 Note: Yields FADH2. Only membrane bound enzyme. Funnels electrons into ETC. Strongly inhibited by malonate. |
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Reaction 7 |
Substrate: Fumarate Product: Malate Enzyme: Fumarase, hydration enzyme |
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Reaction 8 |
Substrate: Malate Product: Oxaloacetate Enzyme: Malate dehydrogenase Coenzyme: B3 Note: Yields NADH, and the regenerating Oxaloacetate |
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Reactions that yield products |
3, 4, 8 make NADH. 5 creates GTP (ATP) 6 makes FADH2 3, 4 makes CO2 |
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Energy products of all three main cycles |
Glycolysis: 7 ATP Pyruvate to acetyl CoA: 5 ATP TCA will create: 20 ATP Total: 32 ATP/glucose |
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Regulatory steps |
Intermediate step, Reaction 1,3,4 |
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Activators/Inactivation enzymes of PDH |
PDP activates, PDK inactivates. |
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Intermediate step regulation |
Activated: AMP, CoA, NAD+, Ca2+ Inhibited: ATP, acetyl CoA, NADH, fatty acids |
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Regulation of step 1: |
Activated by: ADP Inhibited by: NADH, succinyl-CoA, citrate, ATP |
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Regulation of step 3 |
Activated by: Ca2+, ADP Inhibited by: ATP |
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Regulation of step 4 |
Activated by: Ca2+ Inhibited by: Succinyl-CoA, NADH |
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Catoplerism of TCA in excess of |
Oxaloacetate into glucose Acetyl-CoA into fatty acids Alpha ketoglutarate, oxaloacetate into glutamate and aspartate |
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Anaplerism of TCA in shortage of |
Oxaloacetate from Pyruvate Glut/Asp into oxaloacetate/alpha-ketoglutarate Fatty acids into Succinyl-Coa |
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Fluoroacetate |
Environmental inhibitor. Binds to CoA, binds to aconitase as a competitive inhibitor (inhibits TCA at this point) |
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Arsenate |
Binds to sulhydryl compounds to inhibit TCA (pyruvate dehydrogenase and a-ketoglutarate dehydrogenase) |
