Tricarboxylic Acid Cycle by Sir Yhong Alderite.

1. TRICARBOXYLIC
ACID CYCLE
{ Yhong Alderite ,MSERM

2. STEP 1: CITRATE SYNTHASE Enzyme: citrate synthase
Process:
1. Formation of citric acid
2. Dehydration

3. Step 2: Aconitase Reaction
Enzyme: Aconitase
Process : Hydration

4. Step 3: Isocitrate Dehydrogenase Rxn
Enzyme: isocitrate dehydrogenase
Process:
• Dehydrogenation I
• Decarboxylation

5. Step 4: a-Ketoglutarate Dehydrogenase Rxn
Enzyme: a-ketoglutarate dehydrogenase
Process: Oxidative decarboxylation

6. Step 5: Succinyl Co A Synthetase Rxn
Enzyme: Succinyl-CoA synthetase
Process:Oxidative decarboxylation

7. Step 6 : Succinate Dehydrogenase Rxn
Enzyme: succinate dehydrogenase
Process: Oxidation

8. Step 7: Fumarase Rxn Enzyme: Fumarase
Process: Hydration

9. Step 8: Malate Dehydrogenase Rxn
Enzyme: malate dehydrogenase
Process: Dehydrogenation

10. Three control points within the cycle
– citrate synthase, isocitrate dehydrogenase, and a -ketoglutarate
dehydrogenase, are the rate limiting and regulatory enzymes of the
citric acid cycle.
One control point outside the cycle
– The decarboxylation of pyruvate to acetyl-CoA is
irreversible.Therefore, it is critical that the reaction be regulated.

11. Summary of Materials and Products:
Needed Materials: Products:
-Pyruvate - 3 CO2
-4NAD - 4NADH
-FAD - FADH2
-GDP - GTP
-Pi - 4H+
-2 H2O

13. TCA and Amino Acid Synthesis

14. TCA and Fatty Acid Synthesis

15. TCA and Gluconeogenesis

16. TCA cycle in catabolism