IUBMB Enzyme Nomenclature


Accepted name: dihydropyrimidine dehydrogenase (NAD+)

Reaction: (1) 5,6-dihydrouracil + NAD+ = uracil + NADH + H+
(2) 5,6-dihydrothymine + NAD+ = thymine + NADH + H+

For diagram of reaction click here.

Other name(s): dihydropyrimidine dehydrogenase; dihydrothymine dehydrogenase; pyrimidine reductase; thymine reductase; uracil reductase; dihydrouracil dehydrogenase (NAD+)

Systematic name: 5,6-dihydropyrimidine:NAD+ oxidoreductase

Comments: 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: BRENDA, EXPASY, KEGG, Metacyc, 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 (1957) 693-700. [PMID: 13462991]

2. Schmitt, U., Jahnke, K., Rosenbaum, K., Cook, P.F. and Schnackerz, K.D. Purification and characterization of dihydropyrimidine dehydrogenase from Alcaligenes eutrophus. Arch. Biochem. Biophys. 332 (1996) 175-182. [PMID: 8806723]

3. Kim, S. and West, T.P. Pyrimidine catabolism in Pseudomonas aeruginosa. FEMS Microbiol. Lett. 61 (1991) 175-179. [PMID: 1903745]

4. West, T.P. Pyrimidine base catabolism in Pseudomonas putida biotype B. Antonie Van Leeuwenhoek 80 (2001) 163-167. [PMID: 11759049]

5. West, T.P. Isolation and characterization of an Escherichia coli B mutant strain defective in uracil catabolism. Can. J. Microbiol. 44 (1998) 1106-1109. [PMID: 10030006]

6. Hidese, R., Mihara, H., Kurihara, T. and Esaki, N. Escherichia coli dihydropyrimidine dehydrogenase is a novel NAD-dependent heterotetramer essential for the production of 5,6-dihydrouracil. J. Bacteriol. 193 (2011) 989-993. [PMID: 21169495]

[EC created 1961, modified 2011]

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