Skip to content
MS
rate-limiting unreviewed

Phenylalanine hydroxylase (PAH)

1 reactions · 1 pathways

Clinical / pharmacological. Phenylketonuria: musty odour, intellectual disability, hypopigmentation; BH4 defects cause malignant PKU

What it does, reaction by reaction

1 reactions

Amino Acid Catabolism Overview (glucogenic vs. ketogenic amino acids; brief overview of branched-chain amino acid catabolism and phenylalanine/tyrosine catabolism as representative examples) Amino Acid & Nitrogen Metabolism · Cytosol + mitochondrion

step 9 Irreversible

L-phenylalanine + O₂ + tetrahydrobiopterin (BH₄) → L-tyrosine + H₂O + dihydrobiopterin (BH₂)

Converts Phenylalanine O2 Tetrahydrobiopterin (BH4) into Tyrosine H2O Dihydrobiopterin (BH2)

Notes

Phenylalanine hydroxylase (PAH) catalyzes this irreversible hydroxylation; BH₄ is regenerated from BH₂ by dihydropteridine reductase using NADPH. This is the committed entry step for phenylalanine degradation and is also required to generate tyrosine when dietary tyrosine is insufficient.

Showing all 1 reactions.

What accelerates and inhibits it

Regulation is pathway-specific, so each context is listed separately

1 entries

Amino Acid Catabolism Overview (glucogenic vs. ketogenic amino acids; brief overview of branched-chain amino acid catabolism and phenylalanine/tyrosine catabolism as representative examples)

Listed there as: Phenylalanine hydroxylase

Accelerated by

Phenylalanine (allosteric/substrate activation); BH₄ availability

Inhibited by

BH₄ deficiency; inhibitory phosphorylation states/low substrate

Hormonal control

Mainly substrate and cofactor regulated; chronic nutritional/hormonal effects are indirect

Recent literature

Europe PMC · fetched just now · sorted by publication date

  1. 1
  2. 2
  3. 3
  4. 4
    Prognostic value of peak tricuspid regurgitation velocity in hospitalized patients with heart failure with preserved ejection fraction: an multi-institutional study.

    Chang CY, Chen CC, Tsai ML, Hsieh MJ, Lee CH, Chen TH, Chen SW, Chang SH, Chu PH, Hsieh IC, Wen MS, Chen DY. · 2026-04-10

    open access unreviewed
  5. 5
    Loss of productivity among commercially insured patients with pulmonary arterial hypertension in the United States.

    Watzker A, Ferro C, Dieguez G, Girdish C, Alsumali A, Lautsch D, El-Kersh K. · 2026-03-20

    unreviewed
  6. 6
    Smoking exposure on diagnosis and survival of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: Data from REHAP registry.

    Khilzi K, Blanco I, Piccari L, Barberà JA, López-Reyes R, Otero-González I, Alcolea S, Ribas J, Álvarez-Barre… · 2026-03-10

    unreviewed
  7. 7
    The process of developing an HIV disclosure intervention for youth with perinatally acquired HIV: The HIV Empowering Adults' Decisions to Share - UK/Uganda Project (Heads-Up).

    Evangeli M, Gnan G, Musiime V, Fidler S, Seeley J, Frize G, Uwizera A, Robinson J, Foster C. · 2026-03-09

    unreviewed
  8. 8
  9. 9
    The TRAP complex (SSR1-SSR4): mechanistic roles and therapeutic opportunities.

    Zhang J, Wan X, Gong A. · 2026-02-06

    open access unreviewed
  10. 10
    Correction.

    · 2026-01-21

    unreviewed

External claims. These come from an index outside this database and are not checked against it. Treat them as leads.