Three steps from chorismate, sharing the first with phenylalanine
Route: Chorismate → Prephenate → 4-Hydroxyphenylpyruvate → Tyrosine
The first step, chorismate mutase, is the same as in the phenylalanine pathway. Prephenate dehydrogenase then uses NAD⁺ to turn prephenate into 4-hydroxyphenylpyruvate, with release of CO₂. The last step is a transamination from glutamate. Humans cannot make chorismate. They make tyrosine in one step instead, by adding a hydroxyl group to the ring of phenylalanine, so tyrosine is not essential as long as the diet has enough phenylalanine.
Practice this pathway All pathways
| Step | Enzyme | EC | In | Out |
|---|---|---|---|---|
| 1 | Chorismate mutase | 5.4.99.5 | ||
| 2 | Prephenate dehydrogenase | 1.3.1.12 | NAD⁺ | NADH, CO₂ |
| 3 | Aromatic amino acid aminotransferase | 2.6.1.57 | Glutamate | α-KG |
Enzyme names and EC numbers are those used on the interactive board. Checked against sources: see the claim table in the repository (tools/pathway_data/checks).