EC - 4-hydroxyphenylacetate 3-monooxygenase

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IntEnz Enzyme Nomenclature


Accepted name:
4-hydroxyphenylacetate 3-monooxygenase
Other names:
4 HPA 3-hydroxylase
4-hydroxyphenylacetic acid-3-hydroxylase
p-hydroxyphenylacetate 3-hydroxylase
p-hydroxyphenylacetate hydroxylase
p-hydroxyphenylacetate hydroxylase (FAD)
p-hydroxyphenylacetate 3-hydroxylase (FAD)
Systematic name:
4-hydroxyphenylacetate,FAD:oxygen oxidoreductase (3-hydroxylating)




The enzyme from Escherichia coli attacks a broad spectrum of phenolic compounds. The enzyme uses FADH2 as a substrate rather than a cofactor [4]. FADH2 is provided by EC, flavin reductase (NADH) [5,6].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UM-BBD , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0052881 , GO:0018660
CAS Registry Number: 37256-71-6


  1. Adachi, K., Takeda, Y., Senoh, S. and Kita, H.
    Metabolism of p-hydroxyphenylacetic acid in Pseudomonas ovalis.
    Biochim. Biophys. Acta 93 : 483-493 (1964).
  2. Prieto, M. A., Perez-Aranda, A., Garcia, J. L.
    Characterization of an Escherichia coli aromatic hydroxylase with a broad substrate range.
    J. Bacteriol. 175 : 2162-2167 (1993). [PMID: 8458860]
  3. Prieto, M. A., Garcia, J. L.
    Molecular characterization of 4-hydroxyphenylacetate 3-hydroxylase of Escherichia coli. A two-protein component enzyme.
    J. Biol. Chem. 269 : 22823-22829 (1994). [PMID: 8077235]
  4. Xun, L., Sandvik, E. R.
    Characterization of 4-hydroxyphenylacetate 3-hydroxylase (HpaB) of Escherichia coli as a reduced flavin adenine dinucleotide-utilizing monooxygenase.
    Appl. Environ. Microbiol. 66 : 481-486 (2000). [PMID: 10653707]
  5. Galan, B., Diaz, E., Prieto, M. A., Garcia, J. L.
    Functional analysis of the small component of the 4-hydroxyphenylacetate 3-monooxygenase of Escherichia coli W: a prototype of a new flavin:NAD(P)H reductase subfamily.
    J. Bacteriol. 182 : 627-636 (2000). [PMID: 10633095]
  6. Louie, T. M., Xie, X. S., Xun, L.
    Coordinated production and utilization of FADH2 by NAD(P)H-flavin oxidoreductase and 4-hydroxyphenylacetate 3-monooxygenase.
    Biochemistry 42 : 7509-7517 (2003). [PMID: 12809507]

[EC created 1972 as EC, transferred 2011 to EC]