dihydroorotate dehydrogenase (quinone);
dihydroorotate:ubiquinone oxidoreductase;
(S)-dihydroorotate:(acceptor) oxidoreductase;
(S)-dihydroorotate:acceptor oxidoreductase;
DHOdehase (ambiguous);
DHOD (ambiguous);
DHODase (ambiguous);
DHODH

Oxidoreductases;
Acting on the CH-CH group of donors;
With a quinone or related compound as acceptor

(S)-dihydroorotate:quinone oxidoreductase

(S)-dihydroorotate + a quinone = orotate + a quinol [RN:R01868]

R01868

(S)-dihydroorotate [CPD:C00337];
quinone [CPD:C00472]

This Class 2 dihydroorotate dehydrogenase enzyme contains FMN [4]. The enzyme is found in eukaryotes in the mitochondrial membrane, and in some Gram negative bacteria associated with the cytoplasmic membrane [2,5]. 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.

1  [PMID:216313]

Forman HJ, Kennedy J.

Mammalian dihydroorotate dehydrogenase: physical and catalytic properties of the primary enzyme.

Arch. Biochem. Biophys. 191 (1978) 23-31.

Rattus norvegicus [GN:rno]

2  [PMID:3733756]

Hines V, Keys LD 3rd, Johnston M

Purification and properties of the bovine liver mitochondrial dihydroorotate dehydrogenase.

J. Biol. Chem. 261 (1986) 11386-92.

Bos taurus [GN:bta]

3  [PMID:9693067]

Bader B, Knecht W, Fries M, Loffler M

Expression, purification, and characterization of histidine-tagged rat and human flavoenzyme dihydroorotate dehydrogenase.

Protein. Expr. Purif. 13 (1998) 414-22.

Homo sapiens [GN:hsa], Rattus norvegicus [GN:rno]

4  [PMID:17154530]

Fagan RL, Nelson MN, Pagano PM, Palfey BA

Mechanism of flavin reduction in class 2 dihydroorotate dehydrogenases.

Biochemistry. 45 (2006) 14926-32.

Homo sapiens [GN:hsa], Escherichia coli [GN:eco]

5  [PMID:10074342]

Bjornberg O, Gruner AC, Roepstorff P, Jensen KF

The activity of Escherichia coli dihydroorotate dehydrogenase is dependent on a conserved loop identified by sequence homology, mutagenesis, and limited proteolysis.

Biochemistry. 38 (1999) 2899-908.