TCA/OxPhos

Question 1

What are the major fates of pyruvate?

Answer 1

• Lactate via Lactate DH
• Alanine via Aminotransferase
• OAA via Pyruvate carboxylase
• Acetyl CoA via Pyruvate DH

Question 2

What are the Cofactors for PDH Complex?

Answer 2

TLC For Nancy

Thiamin
Lipoamide
CoA
Folate
Niacin/Nicotinate

Question 3

What are the major controls of PDH complex?

Answer 3

Simulated by:

• NAD+
• Calcium ions
• High insulin

Inhibited by:

• Acetyl CoA
• NADH
• Low Insulin

Question 4

What are the two states of PDH complex?

Answer 4

Active:

• Dephosphorylated
• Pyruvate Phophatase

Inactive:

• Pyruvate DH Kinase
• Phosphorylated

Question 5

Where are all the enzymes in the TCA located?

Answer 5

Mitochondria

Question 6

What is the first step of TCA?

Answer 6

OAA + Acetyl CoA —> Citrate

• Citrate Synthase
• H20 —> HS-CoA

Question 7

Step Two: Citrate

Answer 7

Citrate —> Isocitrate

• Aconitase

Question 8

Step 3: Isocitrate

Answer 8

Isocitrate —> a-ketoglutarate

• NAD+ -> NADH
• Expel CO2
• Isocitrate DH

Question 9

Step 4: a-Ketoglutarate

Answer 9

a-KG + CoASH —> Succinyl CoA

• aKG DH
• NAD+ —> NADH
• Expel CO2

Question 10

Step 5: Succinyl CoA

Answer 10

Succinyl CoA —> CoASH + Succinate

• Succinate thiokinase (SucCoA Synthetase)
• GDP + P —> GTP

Question 11

Step 6: Succinate

Answer 11

Succinate —> Fumarate (trans)

• Succinate DH
• FAD —> FADH2

Question 12

Step 7: Fumarate

Answer 12

Fumarate —> Malate

• Fyumarate Hydratase (Fumarase)
• Consumes H20

Question 13

Step 8: Malate

Answer 13

Malate —> OAA

• NAD+ —> NADH
• Malate DH

Question 14

Life outside the TCA: Citrate

Answer 14

• FA Synthesis
• Gluconeogenesis
• Inhibition of glycolysis (PFK1)

Question 15

Life outside the TCA: aKG

Answer 15

• Transamination to glutamate

Question 16

Life outside the TCA: Succinyl CoA

Answer 16

• heme synthesis

Question 17

Life outside the TCA: Succinate

Answer 17

• Control Vascular proliferation

Question 18

Life outside the TCA: OAA

Answer 18

• Glucose Synthesis

- Transamination to aspartate

Question 19

Explain Succinate and fumarate associated pathology.

Answer 19

• Succinate to fumarate DH deficiency —> Accumulation —> Inhibits hydroxylation of proline on Hypoxia-inducible factors —> Cell proliferation and angiogenesis

Question 20

Which two enzymes involved in shuttling in the Mt membrane convert NADH —> NAD+?

Answer 20

• Malate DH

- a-Glycerol phosphate DH

Question 21

What are the major complexes of the ETC?

Answer 21

Complex I (NADH CoQ Reductase)

Complex II (CoEnzyme Q or Succinate DH)

Complex III (CoQ Cytochrome C Reductase)

Complex IV (Cytochrome Oxidase)

Question 22

What are the major controls of OxPhos?

Answer 22

• Proton gradient
• ADP availability
• O2 availability

Question 23

What common symptom is associated with Mitochondrial disease like Alpert’s, LHON, and MELAS?

Answer 23

Blindness and other Neurological defects