Lesson 5 - Regulation of Pyruvate Dehydrogenase

Question 1

Name the three enzymes in the Pyruvate Dehydrogenase Complex

Answer 1

E1: Pyruvate Dehydrogenase
E2: Dihydrolipoyl Acetyl Transferase
E3: Dihydrolipoyl Dehydrogenase

Question 2

What is the function of E1?

Answer 2

Decarboxylation
- Thiamine (TPP: Thiaminepyrophosphate)
[Vitamin B1]

Question 3

What is the function of E2?

Answer 3

Addition of CoA
- Lipoic Acid (Lipoate)
- Pantothenic Acid
[Vitamin B5]

Question 4

What is the function of E3?

Answer 4

Conversion of FAD to FADH2
- Riboflavin
[Vitamin B2]

Conversion of NAD to NADH
- Niacin
[Vitamin B3]

Question 5

What is the function of Pyruvate Dehydrogenase Kinase?

Answer 5

Phosphorylates E1 (Pyruvate Dehydrogenase) to inhibit its process

Question 6

How is PDH Kinase regulated?

Answer 6

Allosteric
Stimulant: ATP ↑, NADH ↑, Acetyl-CoA ↑
Inhibitor: ADP ↑, Pyruvate ↑

Question 7

How is E1 regulated?

Answer 7

Allosteric
Stimulant: N/A
Inhibitor: ATP ↑, NADH ↑

Question 8

What is the function of Pyruvate Dehydrogenase Phosphatase?

Answer 8

Dephosphorylates E1 (Pyruvate Dehydrogenase) to activate its process

Question 9

How is PDH Phosphatase regulated?

Answer 9

Allosteric
Stimulant: Ca2+, Insulin
Inhibitors: N/A