Biochemistry · Enzyme
Glutamate dehydrogenase (GDH) !
Glutamate dehydrogenase frees ammonia from glutamate in liver mitochondria and links amino acid breakdown to the Krebs cycle.
Updated 2026-11-01
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Key facts
- Glutamate + NAD(P)⁺ + H₂O ⇌ α-ketoglutarate + NH₄⁺ + NAD(P)H; reversible.
- It can use NAD⁺ or NADP⁺, which is unusual among dehydrogenases.
- With the transaminases it forms transdeamination: the amino group of almost any amino acid ends as NH₄⁺.
- A mitochondrial hexamer abundant in liver, kidney and brain.
Structure
- 1L1F is human GDH with no ligands: six subunits with an «antenna» that relays allosteric signals.
Regulation
- ADP and leucine activate it (low energy or plenty of amino acids).
- GTP and ATP inhibit it (high energy).
Inhibitors and toxins
- GTP (physiological inhibitor)
- Epigallocatechin gallate from green tea (experimental)
Clinical notes
- Activating GLUD1 mutations, which remove GTP inhibition, cause the hyperinsulinism–hyperammonaemia syndrome.
- In that syndrome, protein-rich meals (leucine) trigger hypoglycaemia, and ammonia stays mildly and constantly high.
Related conditions
Related
- Glutamate (glutamic acid)
- Ammonia (ammonium)
- NAD⁺ (nicotinamide adenine dinucleotide)
- Krebs cycle (citric acid cycle)
- Transamination and deamination
Test yourself
Think of the answer, then tap the question to see it.
Which reaction does glutamate dehydrogenase catalyse?
Oxidative deamination of glutamate: it releases NH₄⁺ and forms α-ketoglutarate, using NAD⁺ or NADP⁺.
Which molecules activate it, and which inhibit it?
ADP and leucine activate it; GTP and ATP inhibit it.
Why does an overactive GDH cause hypoglycaemia?
In the beta cell it makes more α-ketoglutarate and ATP, which triggers insulin release, especially after protein.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: GLUD1: Glutamate dehydrogenase 1, mitochondrial (human) (UniProt, 2026); Congenital hyperinsulinism: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); 1L1F: Structure of human glutamate dehydrogenase-apo form (RCSB Protein Data Bank, 2026).
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