Glutathione (GSH) !

Glutathione is a tripeptide with a thiol group that neutralises oxidants and toxins; it is the main antioxidant inside the cell.

Updated 2026-11-01

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Key facts

A tripeptide of glutamate, cysteine and glycine; the glutamate bond is γ, rare in proteins.
Cysteine's –SH group donates electrons: two GSH are oxidised to GSSG (a disulfide).
Glutathione reductase regenerates it with NADPH (pentose phosphate pathway) and FAD.
It is made in two ATP-using steps (γ-glutamylcysteine synthetase and glutathione synthetase).

In acetaminophen overdose, the toxic metabolite (NAPQI) depletes liver glutathione; N-acetylcysteine supplies cysteine to rebuild it.
In G6PD deficiency GSH is not regenerated: hemolytic crises with Heinz bodies.
Glutathione synthetase deficiency causes hemolytic anemia and, in its severe form, metabolic acidosis with 5-oxoprolinuria.

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

Which amino acids make up glutathione?

Glutamate, cysteine and glycine; the cysteine thiol is the working part.

Which enzyme regenerates GSH and which coenzyme does it use?

Glutathione reductase, with NADPH (and FAD as prosthetic group).

Why is N-acetylcysteine given in acetaminophen poisoning?

It supplies cysteine to rebuild the glutathione that NAPQI used up in the liver.

Molecules are shown in their neutral form, as the databases deposit them; in the cell the acids and phosphates are ionised.

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

Sources: Glutathione (CID 124886) (PubChem, NCBI, 2026) · Public domain; Glutathione synthesis and recycling (Reactome, 2026); Glutathione synthetase deficiency: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026).

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