IUBMB Enzyme Nomenclature


Accepted name: protocatechuate 3,4-dioxygenase

Reaction: 3,4-dihydroxybenzoate + O2 = 3-carboxy-cis,cis-muconate

For diagram click here.

Glossary: 3,4-dihydroxybenzoate = protocatechuate

Other name(s): protocatechuate oxygenase; protocatechuic acid oxidase; protocatechuic 3,4-dioxygenase; protocatechuic 3,4-oxygenase

Systematic name: protocatechuate:oxygen 3,4-oxidoreductase (decyclizing)

Comments: Requires Fe3+. The enzyme, which participates in the degradation of aromatic compounds, catalyses the intradiol addition of both oxygen atoms from molecular oxygen, resulting in ortho-cleavage of the aromatic ring. The type of cleavage leads to mineralization via the intermediate 3-oxoadipate.

Links to other databases: BRENDA, EAWAG-BBD, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9029-47-4


1. Fujisawa, H. and Hayaishi, O. Protocatechuate 3,4-dioxygenase. I. Crystallization and characterization. J. Biol. Chem. 243 (1968) 2673-2681. [PMID: 4967959]

2. Gross, S.R., Gafford, R.D. and Tatum, E.L. The metabolism of protocatechuic acid by Neurospora.J. Biol. Chem. 219 (1956) 781-796.

3. Stanier, R.Y. and Ingraham, J.L. Protocatechuic acid oxidase. J. Biol. Chem. 210 (1954) 799-820.

[EC created 1961 as EC, transferred 1965 to EC, transferred 1972 to EC]

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