[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Biochemistry](https://durgical.com/en/biochemistry/) › Succinyl-CoA:3-ketoacid CoA transferase (SCOT)

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

# Succinyl-CoA:3-ketoacid CoA transferase (SCOT)

SCOT lets muscle, heart and brain use ketones: it moves CoA from succinyl-CoA onto acetoacetate.

Updated 2026-11-01

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## Key facts

- Acetoacetate + succinyl-CoA → acetoacetyl-CoA + succinate; thiolase then gives 2 acetyl-CoA.
- Missing in the liver: that is why the liver exports ketones instead of burning them.
- Uses a Krebs cycle intermediate (succinyl-CoA): the GTP of succinyl-CoA synthetase is forgone.

**Also called**
Thiophorase, OXCT1

**EC number**
[2.8.3.5](https://www.enzyme-database.org/query.php?ec=2.8.3.5)

**Genes**
OXCT1

**Structure (PDB)**
[3DLX](https://www.rcsb.org/structure/3DLX)

## Regulation

- Its activity depends on the supply of succinyl-CoA and acetoacetate.
- It rises in brain and muscle during prolonged fasting.

## Inhibitors and toxins

- No inhibitors in clinical use

## Clinical notes

- Its inherited deficiency causes severe intermittent ketoacidosis from infancy, with ketosis even after meals.
- Together with β-ketothiolase deficiency, it causes ketoacidosis with normal glucose in children.

## Pathways

- [Ketogenesis (ketone body synthesis)](https://durgical.com/en/biochemistry/pathways/ketogenesis/)
- [Krebs cycle (citric acid cycle)](https://durgical.com/en/biochemistry/pathways/krebs-cycle/)

## Related conditions

- [Diabetic ketoacidosis](https://durgical.com/en/conditions/diabetic-ketoacidosis/)

## Related

- [Acetoacetate (acetoacetic acid)](https://durgical.com/en/biochemistry/molecules/acetoacetate/)
- [β-Hydroxybutyrate](https://durgical.com/en/biochemistry/molecules/hydroxybutyrate/)
- [Acetyl-CoA](https://durgical.com/en/biochemistry/molecules/acetyl-coa/)
- [β-Hydroxybutyrate dehydrogenase (BDH1)](https://durgical.com/en/biochemistry/enzymes/hydroxybutyrate-dehydrogenase/)
- [Krebs cycle (citric acid cycle)](https://durgical.com/en/biochemistry/pathways/krebs-cycle/)

## Test yourself

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

## Why can the liver not use the ketone bodies it makes?

It lacks SCOT, the enzyme that activates acetoacetate to acetoacetyl-CoA.

## Where does SCOT take its coenzyme A from?

From Krebs cycle succinyl-CoA, which is left as succinate.

## What does inherited SCOT deficiency cause?

Episodes of severe ketoacidosis with normal glucose and persistent ketosis even after eating.

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

Sources: [OXCT1: Succinyl-CoA:3-ketoacid coenzyme A transferase 1, mitochondrial (human)](https://www.uniprot.org/uniprotkb/P55809/entry) (UniProt, 2026); [OXCT1 gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/oxct1/) (MedlinePlus, US National Library of Medicine, 2026); [Succinyl-CoA:3-ketoacid CoA transferase deficiency | MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/succinyl-coa3-ketoacid-coa-transferase-deficiency/) (MedlinePlus, US National Library of Medicine, 2026); [3DLX: Crystal structure of human 3-oxoacid CoA transferase 1](https://www.rcsb.org/structure/3DLX) (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/succinyl-coa-3-ketoacid-coa-transferase/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/succinyl-coa-3-ketoacid-coa-transferase/