[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Biochemistry](https://durgical.com/en/biochemistry/) › Glutathione peroxidase (GPX)

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

# Glutathione peroxidase (GPX)

Glutathione peroxidase removes hydrogen peroxide and lipid peroxides using glutathione; it contains selenium.

Updated 2026-11-01

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## Key facts

- H₂O₂ + 2 GSH → 2 H₂O + GSSG; it also reduces lipid peroxides to alcohols.
- Its active site has selenocysteine: dietary selenium is essential.
- Glutathione reductase regenerates GSH with NADPH, which in red cells comes only from the pentose phosphate pathway (G6PD).
- GPX4 protects membranes from peroxidation; when it fails, the cell dies by ferroptosis.

**EC number**
[1.11.1.9](https://www.enzyme-database.org/query.php?ec=1.11.1.9)

**Genes**
GPX1, GPX4

**Structure (PDB)**
[6HKQ](https://www.rcsb.org/structure/6HKQ)

## Regulation

- It depends on GSH and NADPH supply (G6PD).
- Its activity falls with selenium deficiency.

## Inhibitors and toxins

- ML162 and RSL3 (GPX4, experimental; they trigger ferroptosis)

## Clinical notes

- In G6PD deficiency NADPH is lacking, GSH is not regenerated and oxidants (drugs, fava beans, infections) cause hemolysis.
- Severe selenium deficiency is linked to cardiomyopathy (Keshan disease).
- The 3D view shows human GPX4 bound to the inhibitor ML162 in the active site (structure 6HKQ).

## Related

- [Glutathione (GSH)](https://durgical.com/en/biochemistry/molecules/glutathione/)
- [Superoxide dismutase (SOD)](https://durgical.com/en/biochemistry/enzymes/superoxide-dismutase/)
- [Catalase](https://durgical.com/en/biochemistry/enzymes/catalase/)
- [Reactive oxygen species and antioxidants](https://durgical.com/en/biochemistry/topics/reactive-oxygen-species-and-antioxidants/)

## Test yourself

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

## Which trace element does glutathione peroxidase need?

Selenium, as selenocysteine in the active site.

## Why does G6PD deficiency leave red cells defenceless against H₂O₂?

Without G6PD there is no NADPH; glutathione reductase cannot regenerate GSH and glutathione peroxidase runs out of substrate.

## Which form of cell death appears when GPX4 fails?

Ferroptosis, from iron-dependent build-up of lipid peroxides.

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

Sources: [GPX1: Glutathione peroxidase 1 (human)](https://www.uniprot.org/uniprotkb/P07203/entry) (UniProt, 2026); [GPX4: Phospholipid hydroperoxide glutathione peroxidase GPX4 (human)](https://www.uniprot.org/uniprotkb/P36969/entry) (UniProt, 2026); [Detoxification of Reactive Oxygen Species](https://reactome.org/PathwayBrowser/#/R-HSA-3299685) (Reactome, 2026); [6HKQ: Human GPX4 in complex with covalent Inhibitor ML162 (S enantiomer)](https://www.rcsb.org/structure/6HKQ) (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/glutathione-peroxidase/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/biochemistry/enzymes/glutathione-peroxidase/