Worksheet 12 PDH Complex and TCA
1. Where does the formation of pyruvate through glycolysis take place? cytoplasm
Where does pyruvate oxidation take place? Mitochondrial matrix
Pyruvate Dehydrogenase Complex is responsible for the oxidation of pyruvate. It involves three
enzymes with five coenzymes associated with each enzyme. Fill in the chart. Define coenzyme.
Coenzyme: small molecule (org/inorg) attached w/ enzyme that helps enzyme (electron
carriers) like battery in remote. FREE FLOATING –ex. vitamins
Cofactor: When the coenzyme is attached to enzyme
Enzyme Enzyme’s name Cofactor involved
E1 Pyruvate dehydrogenase Thiamine pyrophosphate (TPP)
E2 Dihydrolipoamide transacetylase Lipoic acid (actual cofactor)/
Lipoamide (called when attached to
enzyme and acetyl coA)
E3 Dihydrolipoadmide
dehydrogenase
FAD and NAD+
The overall reaction for pyruvate oxidation is:
Pyruvate + NAD+ + CoA-------->>> Acetyl-CoA + NADH + CO2
2. PDC enzymes to regenerate their oxidized state in order to be able to repeat the reaction over
and over. Fill out the following diagram with the appropriate names and structures and show
where and how these enzymes regenerate each other:
Pyruvate, AcetylCoA, E1-TPP, E2-lipomide (oxidized), CoASH, CO2, E1-TPP-hydroxyethyl group,
E2-lipomide-acetyl group,
3.
4. PDC Regulation is controlled by _____modes of regulation for the PDC:
__________________:
i. PDC activated by:
ii. PDC inhibited by:
_______ _______ _______ ________
