[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Biochemistry](https://durgical.com/en/biochemistry/) › Pyruvate carboxylase

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

# Pyruvate carboxylase

Pyruvate carboxylase turns pyruvate into oxaloacetate inside the mitochondrion: the first step in making glucose and in topping up the Krebs cycle.

Updated 2026-11-01

Loading the 3D model…

## Key facts

- Pyruvate + CO₂ + ATP → oxaloacetate + ADP + Pi; it uses biotin (B7) to carry the CO₂.
- Acetyl-CoA is its obligatory activator: with plenty of acetyl-CoA, pyruvate goes to oxaloacetate rather than to PDH.
- It is the main anaplerotic reaction: it replenishes Krebs-cycle oxaloacetate.
- Mitochondrial; oxaloacetate leaves for the cytosol as malate (or aspartate) to continue gluconeogenesis.

**EC number**
[6.4.1.1](https://www.enzyme-database.org/query.php?ec=6.4.1.1)

**Genes**
PC

**Structure (PDB)**
[3BG3](https://www.rcsb.org/structure/3BG3)

## Regulation

- Allosteric activator: acetyl-CoA.
- Glucagon and glucocorticoids increase the amount in the liver.

## Inhibitors and toxins

- Avidin (raw egg white): traps biotin
- Biotinidase or holocarboxylase synthetase deficiency (no active biotin)

## Clinical notes

- Pyruvate carboxylase deficiency (PC gene) causes lactic acidosis, hypoglycaemia and developmental delay; the neonatal form is very severe.
- In biotin deficiency all carboxylases fail (pyruvate, propionyl-CoA, acetyl-CoA and methylcrotonyl-CoA carboxylases): dermatitis, hair loss and acidosis.

## Pathways

- [Gluconeogenesis](https://durgical.com/en/biochemistry/pathways/gluconeogenesis/)

## Related conditions

- [Lactic acidosis](https://durgical.com/en/conditions/lactic-acidosis/)

## Related

- [Pyruvate](https://durgical.com/en/biochemistry/molecules/pyruvate/)
- [Acetyl-CoA](https://durgical.com/en/biochemistry/molecules/acetyl-coa/)
- [Phosphoenolpyruvate carboxykinase (PEPCK)](https://durgical.com/en/biochemistry/enzymes/phosphoenolpyruvate-carboxykinase/)
- [Krebs cycle (citric acid cycle)](https://durgical.com/en/biochemistry/pathways/krebs-cycle/)
- [Pyruvate dehydrogenase complex (PDH)](https://durgical.com/en/biochemistry/enzymes/pyruvate-dehydrogenase-complex/)
- [ATP (adenosine triphosphate)](https://durgical.com/en/biochemistry/molecules/atp/)

## Test yourself

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

## Which vitamin does pyruvate carboxylase need?

Biotin (B7), which carries activated CO₂ to pyruvate.

## Which molecule activates pyruvate carboxylase and what does it mean?

Acetyl-CoA: it signals spare fatty acids and the need for oxaloacetate, for glucose or for the Krebs cycle.

## Why can eating a lot of raw egg white cause biotin deficiency?

Avidin in raw egg white binds biotin and prevents its absorption; cooking denatures it.

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

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

Sources: [PC: Pyruvate carboxylase, mitochondrial (human)](https://www.uniprot.org/uniprotkb/P11498/entry) (UniProt, 2026); [PC gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/pc/) (MedlinePlus, US National Library of Medicine, 2026); [Pyruvate carboxylase deficiency: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/pyruvate-carboxylase-deficiency/) (MedlinePlus, US National Library of Medicine, 2026); [3BG3: Crystal Structure of Human Pyruvate Carboxylase (missing the biotin carboxylase domain at the N-terminus)](https://www.rcsb.org/structure/3BG3) (RCSB Protein Data Bank, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

[← All of biochemistry](https://durgical.com/en/biochemistry/)

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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