Enzyme - EC 4.2.1.49 - Urocanate hydratase
 

The tridimensional structure of this enzyme has not been resolved yet.


EC
 
4.2.1.49
Official Name
Urocanate hydratase
Alternative Name(s)
Urocanase
Imidazolonepropionate hydrolase
Class
4.Lyases
2.Carbon-oxygen lyases
1.Hydro-lyases
Catalysed reaction
4,5-dihydro-4-ceto-5-imidazolepropanoateurocanate + H2O
Substrates
4,5-dihydro-4-oxo-5-imidazolepropanoate
Products
Urocanate
H2O
Cofactor(s)
NAD;2-oxobutanoate
Metabolic Pathways
Other comments

Contains one tightly bound NAD+ per catalytic subunit; this enzyme is the first known which uses NAD+ as an electrophile instead as a redox reagent.

Urocanase(also known as imidazolonepropionate hydrolase or urocanate hydratase) is the enzyme that catalyzes the second step in the degradation of histidine, the hydration of urocanate into imidazolonepropionate. Urocanase is found in some bacteria, 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. A conserved cysteine has been found to be important for the catalytic mechanism and could be involved in the binding of the NAD+.
Reference


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