Conserved Site

Dihydroorotase, conserved site (IPR002195)

Short name: Dihydroorotase_CS


This group contains a number of protein families, example are:

Dihydroorotase belongs to MEROPS peptidase family M38 (clan MJ), where it is classified as a non-peptidase homologue. DHOase catalyses the third step in the de novo biosynthesis of pyrimidine, the conversion of ureidosuccinic acid (N-carbamoyl-L-aspartate) into dihydroorotate. Dihydroorotase binds a zinc ion which is required for its catalytic activity [PMID: 1671037].

In bacteria, DHOase is a dimer of identical chains of about 400 amino-acid residues (gene pyrC) [PMID: 15278241]. In higher eukaryotes, DHOase is part of a large multi-functional protein known as 'rudimentary' in Drosophila melanogaster and CAD in mammals and which catalyzes the first three steps of pyrimidine biosynthesis [PMID: 8098212]. The DHOase domain is located in the central part of this polyprotein. In yeasts, DHOase is encoded by a monofunctional protein (gene URA4). However, a defective DHOase domain [PMID: 2570735] is found in a multifunctional protein (gene URA2) that catalyzes the first two steps of pyrimidine biosynthesis.

The comparison of DHOase sequences from various sources shows [PMID: 2897615] that there are two highly conserved regions. The first located in the N-terminal extremity contains two histidine residues suggested [PMID: 2570735] to be involved in binding the zinc ion. The second is found in the C-terminal part. Members of this family of proteins are predicted to adopt a TIM barrel fold [PMID: 9144792].

Allantoinase (EC: is the enzyme that hydrolyzes allantoin into allantoate. In yeast (gene DAL1) [PMID: 1803816], it is the first enzyme in the allantoin degradation pathway; in amphibians [PMID: 8163532] and fishs it catalyzes the second step in the degradation of uric acid. The sequence of allantoinase is evolutionary related to that of DHOases.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016812 hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in cyclic amides

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns
PROSITE patterns