Center for Bioinformatics
Oxidoreductases | Transferases | Hydrolases | Lyases | Isomerases | Ligases

Basic Information

Enzyme Number

Official Name

phenylalanine 4-monooxygenase

Name from literature

phenylalanine hydroxylase

Pathway from literature

hepatic phenylalanine metabolism

Pathway from KEGG

Amino Acid Metabolism; Phenylalanine, tyrosine and tryptophan biosynthesis; map00400


Rat (10116)

Genome localization

7q13[24616 ],


The active centre contains mononuclear iron(II). The reaction involves an arene oxide that rearranges to give the phenolic hydroxy group. This results in the hydrogen at C-4 migrating to C-3 and in part being retained. This process is known as the NIH-shift. The 4a-hydroxytetrahydrobiopterin formed can dehydrate to 6,7-dihydrobiopterin, both spontaneously and by the action of EC, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydrobiopterin can be enzymically reduced back to tetrahydrobiopterin, by EC, 6,7-dihydropteridine reductase, or slowly rearranges into the more stable compound 7,8-dihydrobiopterin.

Rate-limiting Description

"This study investigated the relationship between the parameters of PheBT, performed with air isotope ratio mass spectrometry, and the activity of phenylalanine hydroxylase (PAH), the phenylalanine metabolism rate-limiting enzyme, in rat liver, and proposes valid parameters for the assessment of liver function." (16429477)

Regulatory Information

Upstream transcription factor


Regulatory type





P04176:from_uniprot:16_Phosphoserine; by PKA

transcriptional factor;"HNF1(24817),CREB(81646)"

"Promoter characterized, sequences bind HNF1 and CREB transcription factors present in rat nuclear extracts" (11762195)

Gene ontology

Gene ontology

GO:0016597 (F) amino acid binding [P04176 ];
GO:0004505 (F) phenylalanine 4-monooxygenase activity [P04176 ];
GO:0006559 (P) L-phenylalanine catabolic process [P04176 ];
GO:0055114 (P) oxidation reduction [P04176 ];
GO:0005506 (F) iron ion binding [P04176 ];




Entrez Gene


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  Last Modified: 2009-03-24  
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