Aspartate/ornithine carbamoyltransferase, Asp/Orn-binding domain (IPR006131)

Short name: Asp_carbamoyltransf_Asp/Orn-bd

Overlapping homologous superfamilies

Domain relationships



This family contains two related enzymes:

  1. Aspartate carbamoyltransferase (EC: (ATCase) catalyzes the conversion of aspartate and carbamoyl phosphate to carbamoylaspartate, the second step in the de novo biosynthesis of pyrimidine nucleotides [PMID: 3015959]. In prokaryotes ATCase consists of two subunits: a catalytic chain (gene pyrB) and a regulatory chain (gene pyrI), while in eukaryotes it is a domain in a multi- functional enzyme (called URA2 in yeast, rudimentary in Drosophila, and CAD in mammals [PMID: 8098212]) that also catalyzes other steps of the biosynthesis of pyrimidines.
  2. Ornithine carbamoyltransferase (EC: (OTCase) catalyzes the conversion of ornithine and carbamoyl phosphate to citrulline. In mammals this enzyme participates in the urea cycle [PMID: 2662961] and is located in the mitochondrial matrix. In prokaryotes and eukaryotic microorganisms it is involved in the biosynthesis of arginine. In some bacterial species it is also involved in the degradation of arginine [PMID: 3109911] (the arginine deaminase pathway).
It has been shown [PMID: 6379651] that these two enzymes are evolutionary related. The predicted secondary structure of both enzymes are similar and there are some regions of sequence similarities. One of these regions includes three residues which have been shown, by crystallographic studies [PMID: 6377306], to be implicated in binding the phosphoryl group of carbamoyl phosphate and is described by IPR006132. The carboxyl-terminal, aspartate/ornithine-binding domain is connected to the amino-terminal domain by two alpha-helices, which comprise a hinge between domains [PMID: 10318893].

GO terms

Biological Process

GO:0006520 cellular amino acid metabolic process

Molecular Function

GO:0016597 amino acid binding
GO:0016743 carboxyl- or carbamoyltransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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