MNE- Pyruvate Dehydrogenase Exam Questions and Answers Rated 100%
What are three diseases associated with low Pyruvate Dehydrogenase Complex function and what are
their causes? - Answers 1) Wernicke's encephalopathy: thiamine deficiency
2) Beriberi: thiamine deficiency
3) Pyruvate Dehydrogenase Complex Deficiency: genetic defect in PDC
What is the Pyruvate Dehydrogenase reaction? Where does it occur in the cell? - Answers Synthesis of
Acetyl-CoA + CO2 from Pyruvate
-pyruvate must be transported into mitochondrial matrix from cytosol
What are the 3 structural components of Coenzyme A? - Answers 1) Adenine + ribose-3-phosphate
2) Pantothenic acid central moiety
3) Mercaptoethylamine with *reactive thiol*
Which structures are involved in Acetyl CoA? - Answers 1) 2 carbons from Pyruvate are transferred to
*thiol group* of CoA
2) High energy thioester bond formed: Acetyl-CoA
Describe the thermodynamics of the Pyruvate Dehydrogenase reaction. - Answers 5 reactions: first is
irreversible, following 4 are reversible.
-Since 1st is irreversible, so is the entire process.
What are the 5 cofactors of the pyruvate dehydrogenase complex (PDC) and their vitamin precursors? -
Answers 1) Thiamine pyrophosphate (TPP): from thiamine
2) Flavin Adenine Dinucleotide (FAD): from riboflavin
3) Coenzyme A: from pentothenic acid
4) NAD+: from niacin
5) Lipoic acid: (no vitamin necessary)
What are the three enzymes of the PDC? - Answers 1) Pyruvate dehydrogenase (E1)
2) Dihydrolipoyl transacetylase (E2)
3) Dihydrolipoyl dehydrogenase (E3)
Describe the reactions that occur in PDC E1. - Answers 1) TPP + pyruvate --> hydroxyethyl-TPP + CO2
What are three diseases associated with low Pyruvate Dehydrogenase Complex function and what are
their causes? - Answers 1) Wernicke's encephalopathy: thiamine deficiency
2) Beriberi: thiamine deficiency
3) Pyruvate Dehydrogenase Complex Deficiency: genetic defect in PDC
What is the Pyruvate Dehydrogenase reaction? Where does it occur in the cell? - Answers Synthesis of
Acetyl-CoA + CO2 from Pyruvate
-pyruvate must be transported into mitochondrial matrix from cytosol
What are the 3 structural components of Coenzyme A? - Answers 1) Adenine + ribose-3-phosphate
2) Pantothenic acid central moiety
3) Mercaptoethylamine with *reactive thiol*
Which structures are involved in Acetyl CoA? - Answers 1) 2 carbons from Pyruvate are transferred to
*thiol group* of CoA
2) High energy thioester bond formed: Acetyl-CoA
Describe the thermodynamics of the Pyruvate Dehydrogenase reaction. - Answers 5 reactions: first is
irreversible, following 4 are reversible.
-Since 1st is irreversible, so is the entire process.
What are the 5 cofactors of the pyruvate dehydrogenase complex (PDC) and their vitamin precursors? -
Answers 1) Thiamine pyrophosphate (TPP): from thiamine
2) Flavin Adenine Dinucleotide (FAD): from riboflavin
3) Coenzyme A: from pentothenic acid
4) NAD+: from niacin
5) Lipoic acid: (no vitamin necessary)
What are the three enzymes of the PDC? - Answers 1) Pyruvate dehydrogenase (E1)
2) Dihydrolipoyl transacetylase (E2)
3) Dihydrolipoyl dehydrogenase (E3)
Describe the reactions that occur in PDC E1. - Answers 1) TPP + pyruvate --> hydroxyethyl-TPP + CO2
