| EC |
1.3.5.2 |
| Accepted name: |
dihydroorotate dehydrogenase (quinone) |
| Reaction: |
(S)-dihydroorotate + a quinone = orotate + a quinol |
| Other name(s): |
dihydroorotate:ubiquinone oxidoreductase; (S)-dihydroorotate:(acceptor) oxidoreductase; (S)-dihydroorotate:acceptor oxidoreductase; DHOdehase (ambiguous); DHOD (ambiguous); DHODase (ambiguous); DHODH |
| Systematic name: |
(S)-dihydroorotate:quinone oxidoreductase |
| Comments: |
This Class 2 dihydroorotate dehydrogenase enzyme contains FMN [4]. The enzyme is found in eukaryotes in the mitochondrial membrane, in cyanobacteria, and in some Gram-negative and Gram-positive bacteria associated with the cytoplasmic membrane [2,5,6]. The reaction is the only redox reaction in the de-novo biosynthesis of pyrimidine nucleotides [2,4]. The best quinone electron acceptors for the enzyme from bovine liver are ubiquinone-6 and ubiquinone-7, although simple quinones, such as benzoquinone, can also act as acceptor at lower rates [2]. Methyl-, ethyl-, tert-butyl and benzyl (S)-dihydroorotates are also substrates, but methyl esters of (S)-1-methyl and (S)-3-methyl and (S)-1,3-dimethyldihydroorotates are not [2]. Class 1 dihydroorotate dehydrogenases use either fumarate (EC 1.3.98.1), NAD+ (EC 1.3.1.14) or NADP+ (EC 1.3.1.15) as electron acceptor. |
| Links to other databases: |
BRENDA, EXPASY, Gene, KEGG, MetaCyc, PDB, CAS registry number: 59088-23-2 |
| References: |
| 1. |
Forman, H.J. and Kennedy, J. Mammalian dihydroorotate dehydrogenase: physical and catalytic properties of the primary enzyme. Arch. Biochem. Biophys. 191 (1978) 23–31. [DOI] [PMID: 216313] |
| 2. |
Hines, V., Keys, L.D., III and Johnston, M. Purification and properties of the bovine liver mitochondrial dihydroorotate dehydrogenase. J. Biol. Chem. 261 (1986) 11386–11392. [PMID: 3733756] |
| 3. |
Bader, B., Knecht, W., Fries, M. and Löffler, M. Expression, purification, and characterization of histidine-tagged rat and human flavoenzyme dihydroorotate dehydrogenase. Protein Expr. Purif. 13 (1998) 414–422. [DOI] [PMID: 9693067] |
| 4. |
Fagan, R.L., Nelson, M.N., Pagano, P.M. and Palfey, B.A. Mechanism of flavin reduction in Class 2 dihydroorotate dehydrogenases. Biochemistry 45 (2006) 14926–14932. [DOI] [PMID: 17154530] |
| 5. |
Björnberg, O., Grüner, A.C., Roepstorff, P. and Jensen, K.F. The activity of Escherichia coli dihydroorotate dehydrogenase is dependent on a conserved loop identified by sequence homology, mutagenesis, and limited proteolysis. Biochemistry 38 (1999) 2899–2908. [DOI] [PMID: 10074342] |
| 6. |
Nara, T., Hshimoto, T. and Aoki, T. Evolutionary implications of the mosaic pyrimidine-biosynthetic pathway in eukaryotes. Gene 257 (2000) 209–222. [DOI] [PMID: 11080587] |
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| [EC 1.3.5.2 created 1983 as EC 1.3.99.11, transferred 2009 to EC 1.3.5.2, modified 2011] |
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