A Citric Acid Cycle Schematic
The Citric Acid Cycle is a key metabolic pathway that connects carbohydrate, fat, and protein metabolism!!! See also [1].
The Citric Acid Cycle (tricarboxylic acid cycle) is a series of enzyme catalyzed reactions which are critical in cellular respiration. Under oxidative conditions, pyruvate continues to be metabolized through the tricarboxylic acid cycle. In this cycle, Acetyl-CoA, a byproduct of glycolysis, along with various cofactors, are broken down into carbon dioxide, water, and energy in the form of GTP and NADH.
Pyruvate dehydrogenase
The multienzyme complex together catalyzes five distinct reactions in the conversion of pyruvate to acetyl-CoA. The overall result is described by the following reaction:
Pyruvate + CoA + NAD+ ==> Acetyl-CoA + CO2 + NADH
However, pyruvate dehydrogenase (E1) is responsible for only the first two of the five reactions. The first of these is the decarboxylation of pyruvate and coupling of thiamine pyrophosphate (TPP) to form hydroxyethyl-TPP.
Pyruvate + TPP ==> Hydroxyethyl-TPP + CO2
Step 0 / 10 - Aldol condensation - Citrate synthase
Step 1 - Dehydration - Aconitase
Step 2 - Hydration - Aconitase
Step 3 - Oxidation - Isocitrate dehydrogenase
Step 4 - Decarboxylation - Isocitrate dehydrogenase
Step 5 - Oxidative decarboxylation - α-Ketoglutarate dehydrogenase (2-Oxoglutarate Dehydrogenase)
Step 6 - Substrate-level phosphorylation - Succinyl-CoA synthetase
Step 7 - Oxidation - Succinate dehydrogenase
Step 8 - Hydration - Fumarase
Step 9 - Oxidation - Malate dehydrogenase
Articles in Proteopedia concerning Citric Acid Cycle include:
To view Citric Acid Cycle related proteins which are Structure Index entries see:
To view automatically seeded indices concerning Citric Acid Cycle See:
