Urocanase (IPR023637)

Short name: Urocanase

Overlapping homologous superfamilies

Family relationships



Urocanase [PMID: 7944380] (also known as imidazolonepropionate hydrolase or urocanate hydratase) is the enzyme that catalyses the second step in the degradation of histidine, the hydration of urocanate into imidazolonepropionate: urocanate + H2O = 4,5-dihydro-4-oxo-5-imidazolepropanoate Urocanase is found in some bacteria (gene hutU) [PMID: 4990470], in the liver of many vertebrates, and has also been found in the plant Trifolium repens (white clover). Urocanase is a protein of about 60 Kd, it binds tightly to NAD+ and uses it as an electrophil cofactor. A conserved cysteine has been found to be important for the catalytic mechanism and could be involved in the binding of the NAD+.

This enzyme is a symmetric homodimer with tightly bound NAD+ cofactors. Each subunit consists of a typical NAD-binding domain inserted into a larger core domain that forms the dimer interface [PMID: 15313616].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016153 urocanate hydratase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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