[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Biochemistry](https://durgical.com/en/biochemistry/) › α-Ketoglutarate dehydrogenase

[Biochemistry](https://durgical.com/en/biochemistry/) · Enzyme

# α-Ketoglutarate dehydrogenase

α-Ketoglutarate dehydrogenase is PDH's twin inside the cycle: it releases the second CO₂ and uses the same vitamins.

Updated 2026-10-31

Loading the 3D model…

## Key facts

- α-Ketoglutarate + CoA + NAD⁺ → succinyl-CoA + CO₂ + NADH; irreversible.
- Same design as PDH: E1 (thiamine pyrophosphate), E2 (lipoate) and a shared E3 (FAD, NAD⁺).
- The 3D model is E. coli E1, the most complete structure available.

**Also called**
2-oxoglutarate dehydrogenase

**EC number**
[1.2.4.2](https://www.enzyme-database.org/query.php?ec=1.2.4.2)

**Genes**
OGDH, DLST, DLD

**Structure (PDB)**
[2JGD](https://www.rcsb.org/structure/2JGD)

## Regulation

- Succinyl-CoA, NADH and ATP inhibit it; Ca²⁺ activates it. Unlike PDH, it is not regulated by phosphorylation.

## Inhibitors and toxins

- Arsenite (lipoic acid)

## Clinical notes

- It is very sensitive to thiamine deficiency and oxidative stress; its failure in neurons contributes to Wernicke encephalopathy.
- α-Ketoglutarate also links the cycle to amino acids: glutamate is made and broken down through it.

## Pathways

- [Krebs cycle (citric acid cycle)](https://durgical.com/en/biochemistry/pathways/krebs-cycle/)

## Related conditions

- [Wernicke encephalopathy (thiamine deficiency)](https://durgical.com/en/conditions/wernicke-encephalopathy/)
- [Arsenic poisoning](https://durgical.com/en/conditions/arsenic-poisoning/)

## Related

- [Pyruvate dehydrogenase complex (PDH)](https://durgical.com/en/biochemistry/enzymes/pyruvate-dehydrogenase-complex/)
- [Isocitrate dehydrogenase](https://durgical.com/en/biochemistry/enzymes/isocitrate-dehydrogenase/)

## Test yourself

Think of the answer, then tap the question to see it.

## Which enzyme shares E3 with α-ketoglutarate dehydrogenase?

Pyruvate dehydrogenase (and the branched-chain keto acid dehydrogenase).

## Which product inhibits α-ketoglutarate dehydrogenase?

Succinyl-CoA (as well as NADH).

## Which vitamin, when lacking, slows this enzyme and PDH at once?

Thiamine (B1).

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/biochemistry/enzymes/ketoglutarate-dehydrogenase/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [OGDH: 2-oxoglutarate dehydrogenase complex component E1 (human)](https://www.uniprot.org/uniprotkb/Q02218/entry) (UniProt, 2026); [Citric acid cycle (TCA cycle)](https://reactome.org/PathwayBrowser/#/R-HSA-71403) (Reactome, 2026); [2JGD: E. coli 2-oxoglutarate dehydrogenase (E1o)](https://www.rcsb.org/structure/2JGD) (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/biochemistry/enzymes/ketoglutarate-dehydrogenase/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/ketoglutarate-dehydrogenase/