-Ketoglutarate is a citric acid cycle intermediate and an important compound in amino acid metabolism and transamination reactions. Some relevant metabolic reactions involving AKG are shown below.

-Ketoglutarate is also involved in the malate/aspartate shuttle (see here) of mitochondria (Figure 15.11) and enzymatic reactions catalyzed by procollagen proline hydroxylase that hydroxylate procollagen proline residues in collagen synthesis (Figure 21.4).

Reactions:

1. Isocitrate + NAD⁺ <=> -Ketoglutarate + CO2 + NADH (catalyzed by Isocitrate Dehydrogenase)

2. -Ketoglutarate + NAD⁺ + CoASH <=> Succinyl-CoA + CO2 + NADH (catalyzed by Ketoglutarate Dehydrogenase Complex)

3. Oxaloacetate + Glutamate <-> Aspartate + -Ketoglutarate (transamination catalyzed by SGOT).

4. -Ketoglutarate + Glutamine + NADPH + H⁺ <=> 2 Glutamate +  NADP⁺ (Catalyzed by Glutamate Synthase)

5. Alanine + -Ketoglutarate <=> Pyruvate + Glutamate (catalyzed by Aminotransferase).

6. Glutamate + Pyruvate <=> -Ketoglutarate + Alanine (catalyzed by SGPT)

1. Citric Acid Cycle

2. Urea Cycle and Metabolism of Amino Groups