TCA Flashcards
What is congenital lactic acidosis?
Mutation in pyruvate dehydrogenase leading to accumulation of lactate
Pyruvate is made into Acetyl CoA by?
Pyruvate dehydrogenase
How is pyuvate dehydrogenase regulated?
Positive: ADP
Negative: NADH and Acetyl CoA
Kinase and Phosphotase phosphorylate and dephos respectively
T or F: Pyruvate to Acetyl CoA is irreversible
T
Phosphorylated pyruvate dehydrogenase is active or inactive?
Inactive
Pyruvate to Acetyl CoA produces?
CO2 and NADH+H
Pyruvate to Acetyl CoA is called what type of reaction?
Oxidative decarboxylation
T or F: Pyruvate dehydrogenase phosphorylation is regulated by cAMP pathways
F
Name the 5 cofactors required for Pyruvate dehydrogenase
CoA, TPP (Thiamine pyrophosphate), Lipoic acid, FAD, and NAD+
Describe the structure of pyruvate dehydrogenase
2 active sites, 2 regulatory sites, and 5 cofactors (very complex)
TCA: Acetyl CoA feeds in and?
Citrate synthase combines oxaloacetate and acetyl CoA into Citrate losing CoASH and consuming water in an oxidative decarboxylation step
TCA: Citrate is…
Made into isocitrate by acontiase
TCA: Citrate to Isocitrate is a reversible reaction. T or F?
T
TCA: Isocitrate is…
Made to Alpha-Ketoglutarate via isocitrate dehydrogenase. Produces a NADH +H and CO2
TCA: Which step in the cycle is most highly regulated?
Isocitrate to Alpha-ketoglutarate
TCA: Alpha-ketoglutarate is…
Oxidatively decarboxylated by Alpha-ketoglutarate dehydrogenase to made succinyl CoA consuming CoASH and producing NADH +H and CO2
T or F: Alpha-ketoglutarate dehydrogenase is regulated by the same 5 cofactors as pyruvate dehydrogenase
T
T or F: GTP and ATP are equivalent
T
TCA: Succinyl CoA is…
Made into succinate by succinate thiokinase producing GTP and CoASH
What step in TCA involves substrate level phosphorylation?
Succinyl CoA to Succinate
Succinate thiokinase is also called?
Succinyl CoA synthetase
T or F: The TCA cycle has a net gain of carbon
F
TCA: Succinate is…
Succinate dehydrogenase makes Fumarate and produces FADH2
What is another name for succinate dehydrogenase?
Complex II
TCA: Fumarate is…
Converted to Malate by consuming H20 via Fumarase
TCA: Malate is…
Converted to Oxaloacetate by malate dehydrogenase to produce NADH +H
Which steps of TCA made NADH+H?
Isocitrate to Alpha-ketoglutarate (isocitrate dehydrogenase); Alpha-ketogluarate to Succinyl CoA (Alpha-ketoglutarate dehydrogenase); Malate to Oxaloacetate (malate dehydrogenase).
FADH2 is produced in what step of TCA?
Succinate to Fumarate via Succinate dehydrogenase
TCA: Water is consumed at what steps?
Fumarate to Malate (fumarase); Oxaloacetate and Acetyl CoA to Citrate via citrate synthase
TCA: CO2 is produced at what steps?
Isocitrate to Alpha-ketoglutarate (isocitrate dehydrogenase); Alpha -ketoglutarate to Succinyl CoA (Alpha-ketoglutarate dehydrogenase)
TCA: Which step produces substrate level phosphorylation?
Sucicnyl CoA to Succinate (Succinate thiokinase)
How many revolutions of TCA occur per glucose?
2
Name the 5 sources for acetyl CoA?
Acetate, Pyruvate (glucose), Fatty acid, ketone bodies, amino acids
What is the net reaction for TCA?
Acetyl CoA + 3NAD+ + FAD + GDP + P +2 H20 = 2 CO2 +CoASH + 3NADH +3 H+ + FAD2H + GTP
What does anapleurotic mean?
Reactions that fill up (replenish the TCA intermediates)
Oxaloacetate is replenished by?
AA and Pyruvate plus CO2
Citrate is siphoned to?
Fatty acids and cholesterol
Alpha-ketoglutarate is replenished by?
AA
Succinyl CoA is siphoned and replenished by?
Siphoned to make porphyrins
Replenished by isoleucine, methionine, valine, and odd chain fatty acids
Fumarate is replenished by?
Asparate, phenylalanine, tyrosine
Malate is siphoned to make?
Glucose
Citrate synthestase is inhibited by?
Citrate
Isocitrate dehydrogenase is regulated by?
Positive: ADP and Ca+2
Negative: NADH and ATP
Alpha-ketoglutarate dehydrogenase is regulated by?
Negative: NADH and Succinyl CoA
Positive: Ca+2
What are the three irreversible steps of TCA?
Isocitrate to alpha-ketoglutarate, Acetyl-CoA feed in, Alpha-ketoglutarate to Succinyl CoA
Which is the only enzyme for TCA not free in the mitochondrial matrix?
Succinate dehydrogenase