IUBMB Enzyme Nomenclature


Accepted name: 4-hydroxyphenylacetate 3-monooxygenase

Reaction: 4-hydroxyphenylacetate + FADH2 + O2 = 3,4-dihydroxyphenylacetate + FAD + H2O

Other name(s): p-hydroxyphenylacetate 3-hydroxylase; 4-hydroxyphenylacetic acid-3-hydroxylase; p-hydroxyphenylacetate hydroxylase (FAD); 4 HPA 3-hydroxylase; p-hydroxyphenylacetate 3-hydroxylase (FAD); HpaB

Systematic name: 4-hydroxyphenylacetate,FADH2:oxygen oxidoreductase (3-hydroxylating)

Comments: 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: BRENDA, EAWAG-BBD, EXPASY, KEGG, PDB, 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 (1964) 483-493. [PMID: 14263147]

2. Prieto, M.A., Perez-Aranda, A. and Garcia, J.L. Characterization of an Escherichia coli aromatic hydroxylase with a broad substrate range. J. Bacteriol. 175 (1993) 2162-2167. [PMID: 8458860]

3. Prieto, M.A. and Garcia, J.L. Molecular characterization of 4-hydroxyphenylacetate 3-hydroxylase of Escherichia coli. A two-protein component enzyme. J. Biol. Chem. 269 (1994) 22823-22829. [PMID: 8077235]

4. Xun, L. and 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 (2000) 481-486. [PMID: 10653707]

5. Galan, B., Diaz, E., Prieto, M.A. and 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 (2000) 627-636. [PMID: 10633095]

6. Louie, T.M., Xie, X.S. and Xun, L. Coordinated production and utilization of FADH2 by NAD(P)H-flavin oxidoreductase and 4-hydroxyphenylacetate 3-monooxygenase. Biochemistry 42 (2003) 7509-7517. [PMID: 12809507]

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

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