TCA Cycle Flashcards
What is the rate limiting step of the TCA Cycle?
The conversion of isocitrate to α-ketoglutarate, catalyzed by isocitrate dehydrogenase, is the rate-limiting step of the citric acid cycle. This step is inhibited by increased ATP and NADH and stimulated by increased ADP.
Where in the cell does the TCA cycle take place?
The citric acid cycle occurs in the mitochondria. It produces 3 NADH, 1 FADH2, 2 CO2, and 1 GTP per acetyl-CoA = 10 ATP/acetyl-CoA (2× everything per glucose).I think it’s 12 ATP
What is the enzyme and the cofactor for the following reaction?
pyruvate –> lactate
This reaction is catalyzed by lactic acid dehydrogenase and uses vitamin B3 (niacin) as a cofactor.
What is the enzyme and the cofactor for the following reaction?
pyruvate –> oxaloacetate
This reaction is catalyzed by pyruvate carboxylase and uses biotin as a cofactor.
What is the enzyme and the cofactor for the following reaction?
pyruvate –> alanine
This reaction is catalyzed by** alanine aminotransferase** and uses vitamin B6 (pyridoxine) as a cofactor.
What is the enzyme and the cofactor for the following reaction?
Fructose-6-phosphate → ribulose-5-phosphate
This reaction is catalyzed by transketolase and uses thiamine as a cofactor.
I’m not sure which pathway this is from honestly. Maybe PPP
What is the enzyme and the cofactor for the following reaction?
Pyruvate → acetyl CoA
Pyruvate dehydrogenase complex links glycolysis and the citric acid cycle. It contains 3 enzymes, requiring 5 cofactors that include thiamine pyrophosphate (B1), lipoic acid, CoA (B5, also called pantothenic acid), FAD (B2, riboflavin) and NAD+ (B3).
What are hte products of the TCA cycle?
3 NADH
1 FADH
1 GTP
AKA 12 ATP
How much ATP is each equivalent to?
NADH
FADH
GTP
NADH = 3 ATP
FADH = 2 ATP
GTP = 1 ATP
What is the starting molecule of TCA cycle?
Acetyl CoA
