IPR023637
Urocanase
InterPro entry
Short name | Urocanase |
Overlapping homologous superfamilies |
Description
Urocanase
[2] (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)
[1], 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
[3].
References
1.Urocanase and N-formimino-L-glutamate formiminohydrolase of Bacillus subtilis, two enzymes of the histidine degradation pathway. Kaminskas E, Kimhi Y, Magasanik B. J. Biol. Chem. 245, 3536-44, (1970). PMID: 4990470
2.The urocanase story: a novel role of NAD+ as electrophile. Retey J. Arch. Biochem. Biophys. 314, 1-16, (1994). View articlePMID: 7944380
3.Structure and action of urocanase. Kessler D, Retey J, Schulz GE. J. Mol. Biol. 342, 183-94, (2004). View articlePMID: 15313616
GO terms
biological process
- None
molecular function
cellular component
- None
Cross References
ENZYME
Genome Properties
Contributing Member Database Entries
- PANTHER:PTHR12216
- HAMAP:MF_00577
- PIRSF:PIRSF001423
- NCBIfam:TIGR01228