10: TCA Flashcards
TCA cycle function
Oxidizes carbon fuels for harvesting high energy electrons
Is TCA catabolic or anabolic?
Amphibolic
Where does TCA take place?
Mito
Acetyl coA is the active form of what?
Acetate
What macromolecules can form acetyl CoA?
Carbs, lipids, and proteins
Two ways lipids can form acetyl CoA
TAGs -> FAs -> acetyl coA
Ketone bodies -> acetyl coA
Five PDC coenzymes and the vitamins they are derived from
TPP: B1 FAD: B2 NAD+: B3 CoA: B5 Lipoic acid: not from a vitamin
Where does phosphorylation occur on the PDC?
E1 complex, via TPP
What happens in a phosphatase deficiency?
PDC always inactive -> glucose goes to lactate -> lactic acidosis -> affects CNS
What does TCA do when there’s low cellular ATP?
Increases
Reducing power of a cell
NADH:NAD+ ratio
Two major things high citrate does
- Inhibits PFK-1 in glycolysis
2. Activates ACC in FA synthesis
What does high citrate indicate in a cell?
ATP-rich state
How does fluoroacetate work?
Reacts with CoA -> fluoroacetyl CoA -> competitive inhibitor of aconitase -> inhibited aconitase leads to citrate buildup -> inhibits citrate synthase
Two major anaplerotic reactions of TCA
- Degradation of AAs
2. Carboxylation of pyruvate