EC - Dihydrouracil dehydrogenase (NAD+)

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IntEnz Enzyme Nomenclature


Accepted name:
dihydrouracil dehydrogenase (NAD+)
Other names:
dehydrogenase, dihydrouracil
dihydropyrimidine dehydrogenase
dihydrothymine dehydrogenase
pyrimidine reductase
thymine reductase
uracil reductase
Systematic name:
5,6-dihydrouracil:NAD+ oxidoreductase




An iron-sulfur flavoenzyme. The enzyme was originally discovered in the uracil-fermenting bacterium, Clostridium uracilicum, which utilizes uracil and thymine as nitrogen and carbon sources for growth [1]. Since then the enzyme was found in additional organisms including Alcaligenes eutrophus [2], Pseudomonas strains [3,4] and Escherichia coli [5,6].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004159
CAS Registry Number: 9026-89-5


  1. Campbell, L.L.
    Reductive degradation of pyrimidines. III. Purificaion and properties of dihydrouracil dehydrogenase.
    J. Biol. Chem. 227: 693-700 (1957). [PMID: 13462991]
  2. Schmitt, U., Jahnke, K., Rosenbaum, K., Cook, P. F., Schnackerz, K. D.
    Purification and characterization of dihydropyrimidine dehydrogenase from Alcaligenes eutrophus.
    Arch. Biochem. Biophys. 332: 175-182 (1996). [PMID: 8806723]
  3. Kim, S., West, T. P.
    Pyrimidine catabolism in Pseudomonas aeruginosa.
    FEMS Microbiol. Lett. 61: 175-179 (1991). [PMID: 1903745]
  4. West, T. P.
    Pyrimidine base catabolism in Pseudomonas putida biotype B.
    Antonie Van Leeuwenhoek 80: 163-167 (2001). [PMID: 11759049]
  5. West, T. P.
    Isolation and characterization of an Escherichia coli B mutant strain defective in uracil catabolism.
    Can. J. Microbiol. 44: 1106-1109 (1998). [PMID: 10030006]
  6. Hidese, R., Mihara, H., Kurihara, T., Esaki, N.
    Escherichia coli dihydropyrimidine dehydrogenase is a novel NAD-dependent heterotetramer essential for the production of 5,6-dihydrouracil.
    J. Bacteriol. 193: 989-993 (2011). [PMID: 21169495]

[EC created 1961, modified 2011]