TCA Pathway Flashcards Preview

Biochem > TCA Pathway > Flashcards

Flashcards in TCA Pathway Deck (18):
0

Final common pathway for the aerobic oxidation of ALL nutrients: CARBOHYDRATES, LIPID, PROTEIN

Tricarboxylic acid pathway/ KREBS CYCLE/ Citric Acid Cycle

1

Provides majority of ATP for energy

Gluconeogenesis from skeletons of AA

Building blocks for AA and heme (succinyl CoA)

TCA

2

Where does TCA pathway occurs?

In ALL cells with mitochondria

Mitochondrial matrix

Except: Succinate dehydrogenase (inner membrane)

3

What is the substrate?

Acetyl CoA

4

What are the products?

CO2, GTP, NADH and FADH2

5

What is the rate-limiting?

Reaction: isocitrate ➡️ a-ketoglutarate

Enzyme: isocitrate dehydrogenase

6

Acetyl CoA + Oxaloacetate ➡️ CITRATE

Enzyme: citrate synthase

7

Citrate ➡️ ISOCITRATE (isomerization)

Enzyme: Aconitase

Inhibitor: Fluoroacetate (rat poison)

8

Isocitrate ➡️ a-KETOGLUTARATE

This is the rate limiting step

Enzyme: Isocitrate dehydrogenase

Produces: CO2 and NADH

9

a-ketoglutarate dehydrogenase ➡️ SUCCINYL CoA

Enzyme: a-ketoglutarate dehydrogenase

Co-enzymes: similar to pyruvate dehydrogenase

Produces: Co2, NADH

Inhibitor: Arsenite

10

Succinyl CoA ➡️ SUCCINATE

Enzyme: Succinate thiokinase

Produces: GTP by substrate level phosphorylation

11

Succinate ➡️ FUMARATE

Enzyme: Succinate dehydrogenase

Produces: FADH2

12

Fumarate ➡️ MALATE

Enzyme: Fumarase (Fumarate hydratase)

13

Malate ➡️ OXALOACETATE

Enzyme: Malate dehydrogenase

Produces: NADH

14

Divers acetyl CoA to the cytoplasm for fatty acid synthesis via a citrate shuttle

Citrate

15

Heme synthesis and activation of ketone bodies in extrahepatic tissues

Succinyl CoA

16

May be used for gluconeogenesis

Malate

17

TCA pathway

️Oxaloacetate

Citrate

Isocitrate

a-ketoglutarate

Succinyl CoA

Succinate

Fumarate

Malate