Pyruvate Dehydrogenase Complex

Question 1

What are the five different prosthetic groups/cofactors in the PDH complex?

Answer 1

thiamine pyrophosphate (TPP)
flavin adenine dinucleotide (FAD)
coenzyme A (CoA or CoA-SH to emphasize the thiol group)
nicotinamide adenine dinucleotide (NAD)
lipase

Question 2

What is the “business end” of the CoA?

Answer 2

the reactive thiol (-SH) is critical to the role of CoA as an acyl carrier
The acyl group attached to CoA can be thought of as being activated for transfer

Question 3

What is the “business end” of lipoate?

Answer 3

the two sulfurs can form a disulfide bond, form thiols, or bind acyl groups

Question 4

What is the goal of oxidative decarboxylation in the pyruvate dehydrogenase complex?

Answer 4

pyruvate’s carboxyl group is removed as carbon dioxide and the two remaining carbons become the acetyl group of acetyl CoA

Question 5

What are the three units of the pyruvate dehydrogenase complex?

Answer 5

E1) pyruvate dehydrogenase
E2) dihydrolipoyl transacetylase
E3) dihydrolipoyl dehydrogenase

Question 6

The active site of E1 has bound

Answer 6

TPP

Question 7

The active site of E3 has bound

Answer 7

FAD