EC - Phenylalanine 3-monooxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
phenylalanine 3-monooxygenase
Other names:
phenylalanine 3-hydroxylase
Systematic name:
L-phenylalanine,tetrahydrobiopterin:oxygen oxidoreductase (3-hydroxylating)



The enzyme, characterized from the bacterium Streptomyces coeruleorubidus, forms 3-hydroxy-L-phenylalanine (i.e. m-L-tyrosine), which is one of the building blocks in the biosynthesis of the uridyl peptide antibiotics pacidamycins. The 4a-hydroxytetrahydropteridine formed can dehydrate to 6,7-dihydropteridine, both spontaneously and by the action of EC, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydropteridine must be enzymically reduced back to tetrahydropteridine, by EC, 6,7-dihydropteridine reductase, before it slowly rearranges into the more stable but inactive compound 7,8-dihydropteridine.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB


  1. Zhang, W., Ames, B. D., Walsh, C. T.
    Identification of phenylalanine 3-hydroxylase for meta-tyrosine biosynthesis.
    Biochemistry 50 : 5401-5403 (2011). [PMID: 21615132]

[EC created 2014, modified 2019]