Exam 2 Flashcards
What are the inibitors of PDH complex when
Pyruvate -> Acetyl CoA?
- Acetyl-CoA
- It is product
- Competative Inhibitor at E2
- Activates PDH kinases, meaning less active enzyme of PDH complex is available.
- NADH
- It is product
- Activates PDH kinases, meaning less active enzyme of PDH complex is available.
- Competative Inhibitor at E3
- ATP
- High energy charge signals CAC to not be activated as more ATP is not needed, anabolic processses should happen instead
- Activates PDH kinases, meaning less active enzyme of PDH complex is available.
What are the activators of PDH complex when
Pyruvate -> Acetyl CoA?
- ADP
- Low energy charge signals for more ATP to be made
- Inhibits PDH kinases, meaning more active enzyme of PDH complex is available.
- Insulin
- Increases PDH phosphatase, meaning more active enzyme of PDH complex is available.
- Ask Cahill
- Mg2+ and Ca2+
- High concetrations of this stablizing ions signal that ATP concetration and thus energy charge is low
- When this happens, CAC needs to be upregulated
- Increases PDH phosphatasae, meaning more active enzyme of PDH complex is available.
- Pyruvate
- Reactant
- Inhibits PDH kinases, meaning more active enzyme of PDH complex is available.
Define: “energy charge” of a cell,
Explain: effects on regulation
Effects: High energy= High [ATP}
ATP is not only an end product of the ETC and overall catabolism, but it will also phosphrylate enzymes which can lead deactivation
Chemistry and Strucutre of: NAD+
Chemistry and Structure: NADP+
Chemistry: FAD
- Electron carrier, H(-) transfer, and Redox rxns
- Similar to NAD+ but allows for H(-) transfer x2
Chemistry and Strucutre: TPP
Chemistry and Structure: Lipoamide
Chemistry: Biotin
Carrier of CO2 equivalents
Chemistry: Coenzyme Q
Electron transfer between Complexes I or II and Complex III
When are carbons lost in the CAC?
- Carbons lost @
- Pyruvate → Ac-SCoa as CO2
- Not really a part of the CAC
- Isocitrate → 𝝰-ketoglutarate as CO2
- 𝝰-ketoglutarate → Succinyl-CoA as CO2
- Pyruvate → Ac-SCoa as CO2
mechanisms in pyruvate dehydrogenase multienzyme complex (pyruvate to AcSCoA + CO2)
When does generation of ATP/GTP/NADH/ FADH2 occur in the CAC?
- Pyruvate → acetyl-CoA
- (1 NADH: not as a direct result of mechanism but from reoxidation of lipoamide via FAD)
- Isocitrate → 𝝰-ketoglutarate
- (1 NADH)
- 𝝰-ketoglutarate → succinyl-CoA
- (1 NADH: not as a direct result of mechanism but from reoxidation of lipoamide via FAD)
- succinyl-CoA → succinate
- (1 GTP: via phosphorylated histidine)
- Succinate → fumarate
- (1 FADH2)
- Malate → OAA
- (1 NADH)
Explain the amphibolic nature of cycle and feedstocks for CAC intermediates
- Cycle intermediates can be depleted via anabolic pathways
- citrate to FA synthesis
- 𝝰-ketoglutarate to glutamate synthesis
- succinyl-CoA to heme
- OAA to aspartate
- Need to replenish intermediates
- Pyruvate carboxylase: pyruvate +HCO3- + ATP → OAA + ADP + Pi + 2H+ (gluconeogenesis)
- Malate dehydrogenase: pyruvate + HCO3- + NADPH + H+ → malate + NADP+ + H2O
- Multiple amino acids (amino group converted to 𝝰-keto acid)
What are the fates of C atoms from entry as AcSCoA to exit as CO2?
2 C’s entering as Acetyl-CoA will be incorporated into the new OAA as either C1&2 or C3&4
Without using a mechanism, explain the PDH complex
Mechanism: Citrate Synthase
Mechanism: Aconitase
Mechanism: Isocitrate DH
Mechanism: 𝝰-ketoglutarate DH
same as PDH complex
Mechanism: Succinate DH
Mechanism: Fumarase
Mechanism: Malate DH
Which reactions of the CAC have large negative delta G’s?
Explain some Mitochondrion inner membrane features (e.g. selective permeability)
