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Flashcards in TCA Cycle Deck (18):
1

What is the overall output of the TCA cycle?

1 Glucose + 6O2 _6 CO2 + 6H2O + 38 ATP

2

What transforms pyruvate into Acetyl-CoA?

Pyruvate dehydrogenase complex

3

What are the parts of pyruvate dehydrogenase complex?

3 enzymes, 5 vitamin B derived cofactors

4

How is pyruvate dehydrogenase different from _-ketoglutarate dehydrogenase?

PDHC CAN be deactivated via phosphorylation

5

Citrate synthase

Acetyl-CoaA + Oxaloacetate _ Citrate + CoASH. Irreversible rxn. 1st source of reducing equivilents

6

Aconitase

Citrate _ Isocitrate

7

Isocitrate dehydrogenase

Isocitrate _ _-ketoglutarate. Rate limiting step of TCA cycle**. Produces NADH and CO2

8

_-ketoglutarate dehydrogenase

_-ketogluarate _Succinyl-CoA. Irreversible rxn. Similar structure to PDHC. CANNOT be regulated via phosphorylation. Produces NADH and CO2

9

Succinyl CoA synthetase/ Succinyl thiokinase

Succinyl-CoA _ Succinate. Only substrate level phosphroylation if the TCA cycle*

10

Nucleotide diphosphokinase

Phosphorates ATP from GTP (after succinyl thiokinase step)

11

Succinate dehydrogenase

Succinate _Fumarate. Produces FADH2

12

Fumarase

Fumarate _ Malate. Uses H2O

13

Malate dehydrogenase

Malate _ Oxaloacetate (NADH)

14

Malate -Aspartate Shuttle

Replensishes NAD+ in cytosol and NADH in inner mitochondria membrane for electron transport chain

15

What inhibits citrate synthase?

SuccinylCoA

16

What inhibits Isocitrate DH?

ATP

17

What stimulates Isocitrate DH?

ADP

18

What inhibits _-KGDH?

succinyl-CoA, NADH, GTP