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

# Aspartate aminotransferase (AST, GOT)

AST swaps aspartate and oxaloacetate with glutamate and α-ketoglutarate. It supplies urea cycle aspartate and marks liver injury.

Updated 2026-11-01

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## Key facts

- Aspartate + α-ketoglutarate ⇌ oxaloacetate + glutamate, with pyridoxal phosphate.
- There is a cytosolic form (GOT1) and a mitochondrial form (GOT2); together they run the malate–aspartate shuttle.
- It is found in liver, heart, muscle, kidney and red cells: less liver-specific than ALT.
- It supplies the aspartate that enters the urea cycle.

**EC number**
[2.6.1.1](https://www.enzyme-database.org/query.php?ec=2.6.1.1)

**Genes**
GOT1

**Structure (PDB)**
[3II0](https://www.rcsb.org/structure/3II0)

## Structure

- 3II0: human GOT1, a dimer with PLP bound to a lysine in each active site.

## Regulation

- Glucocorticoids induce it; its activity depends on available PLP.

## Inhibitors and toxins

- Aminooxyacetate (experimental inhibitor of PLP enzymes).

## Clinical notes

- An AST/ALT ratio above 2 suggests alcohol-related liver disease (alcohol lowers PLP and damages mitochondria).
- It also rises in myocardial infarction, rhabdomyolysis and haemolysis.

## Pathways

- [Malate–aspartate shuttle](https://durgical.com/en/biochemistry/pathways/malate-aspartate-shuttle/)

## Related conditions

- [Cirrhosis](https://durgical.com/en/conditions/cirrhosis/)
- [Viral hepatitis](https://durgical.com/en/conditions/viral-hepatitis/)
- [Myocardial Infarction (Heart Attack)](https://durgical.com/en/conditions/myocardial-infarction/)

## Related

- [Glutamate (glutamic acid)](https://durgical.com/en/biochemistry/molecules/glutamate/)
- [Alanine aminotransferase (ALT, GPT)](https://durgical.com/en/biochemistry/enzymes/alanine-aminotransferase/)
- [Transamination and deamination](https://durgical.com/en/biochemistry/topics/transamination-and-deamination/)
- [Argininosuccinate synthetase (ASS)](https://durgical.com/en/biochemistry/enzymes/argininosuccinate-synthetase/)
- [Krebs cycle (citric acid cycle)](https://durgical.com/en/biochemistry/pathways/krebs-cycle/)

## Test yourself

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## What does AST supply to the urea cycle?

Aspartate, which carries the second nitrogen of urea to argininosuccinate synthetase.

## What does an AST/ALT ratio above 2 suggest?

Alcohol-related liver disease: alcohol damages mitochondria, home of mitochondrial AST, and lowers the PLP that ALT needs.

## Which shuttle do the two AST isoforms run?

The malate–aspartate shuttle, which moves the reducing power of cytosolic NADH into the mitochondrion.

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

Sources: [GOT1: Aspartate aminotransferase, cytoplasmic (human)](https://www.uniprot.org/uniprotkb/P17174/entry) (UniProt, 2026); [Aspartate aminotransferase (AST) blood test: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/003472.htm) (MedlinePlus, US National Library of Medicine, 2026); [3II0: Crystal structure of human Glutamate oxaloacetate transaminase 1 (GOT1)](https://www.rcsb.org/structure/3II0) (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/aspartate-aminotransferase/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/aspartate-aminotransferase/