TCA pathway

Step 1 of TCA

Formation of citrate. Acetyl CoA condenses with OAA to form citrate

Enzyme in step 1

citrate synthase

Step 2 of TCA

Formation of isocitrate. Citrate is dehydrated and rehydrated to form isocitrate

Enzyme in step 2

Aconitase

Step 3 of TCA

Oxidative decarboxylation. Isocitrate is oxidized and decarboxylated to form a-ketogluterate and CO₂.

Enzyme in step 3

Isocitrate dehydrogenase

Step 4 of TCA

Oxidative decarboxylation. a-ketogluterate is oxidized and decarboxylated to form succinyl-CoA and CO₂

Enzyme in step 4

a-ketogluterate DHase

Step 5 of TCA

Substrate level phosphorylation. Thioester bond of succinyl CoA is hydrolyzed, releasing energy. This energy drives phosphorylation of GDP to GTP, then converted to ATPE

Enzyme in step 5

Succinyl CoA synthetase

Step 6 of TCA

Oxidation of succinate. Succinate is oxidized to fumerate, reducing FAD to FADH₂

Enzyme in step 6

Succinate dehydrogenase

Step 7 of TCA

Hydration of fumarate. Water is added to convert fumerate to malate

Enzyme in step 7

fumarase

Step 8 of TCA

malate is oxidized to OAA, reducing NAD to NADH (reversible)

Enzyme in step 8

malate dehydrogenase

What is produced from the TCA cycle per glucose molecule

6 NADH, 2 FADH₂, 2 GTP

Adds up to 24 ATP