Topic A5

Question 1

Oxidation of pyruvate to acetyl~CoA

Steps

Answer 1

Question 2

Oxidation of pyruvate to acetyl~CoA

Necessary cofactors

Answer 2

The oxidative decarboxylation of pyruvate to acetyl~CoA and CO₂ requires three different enzymes and five different coenzymes organized in a multienzymatic complex

1. HS-CoA → CO₂ removed by TPP
2. FAD → oxidation by NAD⁺ + FAD
3. NAD⁺ → HsCoA → AcCoA (lipoic acid)
4. Lipoc acid
5. TPP (Thiamine Pyrophosphate)
   (VitaminB₁)

Question 3

Oxidation of pyruvate to acetyl~CoA

1. Location (additonal)
2. Where does the product go?

Answer 3

1. The reaction catlayzed by pyruvate dehydrogenase complex occurs inside mitochondria
2. The Acetyl~CoA formed as the end product of the complex are now ready to neter the citric acid cycle

Question 4

Oxidation of pyruvate to acetyl~CoA

Importance

Answer 4

• Preparatory step of citrate cycle
  
  • ​Key step for energy production of organism
• AcCoA is important for other processes of cholesterol + FA synthesis

Question 5

Oxidation of pyruvate to acetyl~CoA

Glycerol phosphate shuttle

Answer 5

• NADH+H⁺ brough into intermembrane space
  
  • Shifted to FADH₂ by mitochondrial enzyme
  • Goes to coenzyme, ø of respiratory chain
• NADH+H⁺ can not transport from cytoplasm to mitochondria without shuttle process
  
  • Only worth 2 ATP in GL → FADH₂