Chpt 17 Flashcards

1
Q

Pyruvate Oxidation

A
  • Aerobic Conditions
  • pyruvate enters in matrix of mitochondria
  • irreversible
  • preserves free energy of decarboxylation, and free energy is used to reduced NAD+ and NADH and attach Acetyl group to CoA forming Acetyl CoA
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2
Q

What enzyme catalyzes Pyruvate Oxidation?

-characteristics

A

Pyruvate Dehydrogenase-Multisubunit Enzyme
E1- Pyruvate Dehydrogenase
-oxidative decarboxylation of pyruvate
-Prosthetic Group- Thiamine Pyrophosphate

E2-Dihydrolipoyl Transacetylase

  • transfer of acetyl group to CoA
  • Prosthetic Group- Lipoic acid (lipoamide)
  • Cofactor- CoA

E3- Dihydrolipoyl Dehydrogenase

  • Regeneration of Oxidized form of Lipoamide
  • Prosthetic Group-FAD
  • Coenzyme- NAD+
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3
Q

What does Pyruvate Dehydrogenase Produce as end products?

A

Acetyl-CoA and CO2 at the expense of NAD+ to NADH

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4
Q

Regulation of Pyruvate Dehydrogenase bifunctional enzyme

A

Stimulators: (low energy charge)
Dephosphorylation
ADP
pyruvate

Inhibitors: (High energy charge)
Phosphoryation
ATP 
Acetyl CoA
NADH
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5
Q

Thiamine Pyrophosphate

  • Helper molecule
  • Function
  • Vitamin
  • deficiency
A

Prosthetic Group of E1-Pyruvate Dehydrogenase

  • Function- Aldehyde group carrier
  • Vitamin- Thiamine (B1)
  • Deficiency-BeriBeri (weight loss, neurological disfunction, heart problems)
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6
Q

Lipoid Acid

  • Helper molecule
  • Function
  • Vitamin
  • deficiency
A

Prosthetic Group of E2-Dihydrolipoyl Transacetylase and attaches to R group of Lysine

  • Function- acyl group carrier
  • Vitamin-Lipoid Acid
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7
Q

E1

  • reaction type
  • Helper Molecule
A

Pyruvate Dehydrogenase subunit of Pyruvate Dehydrogenase bifunctional Enzyme:

  • Oxidative decarboxylation of pyruvate
  • Prosthetic Groups- TPP-Thiamine Pyrophosphate

Eukaryotic Regulation:

1) High Energy=kinase active=Phosphorylation=E1 inactive
- High NADH, Acetyl CoA, and ATP
2) Low Energy charge=phosphatase on=dephosphorylation=E1 active

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8
Q

E1 mechanism

A

add

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