Enzyme - EC 4.2.1.49 - Urocanate hydratase
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The tridimensional structure of this enzyme has not been resolved yet. |
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EC
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4.2.1.49
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Official Name
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Urocanate hydratase
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Alternative Name(s)
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Urocanase
Imidazolonepropionate hydrolase |
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Class
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4.Lyases 2.Carbon-oxygen lyases 1.Hydro-lyases |
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Catalysed reaction
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4,5-dihydro-4-ceto-5-imidazolepropanoateurocanate
+ H2O
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Substrates
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4,5-dihydro-4-oxo-5-imidazolepropanoate
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Products
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Urocanate H2O |
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Cofactor(s)
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NAD;2-oxobutanoate
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Metabolic Pathways
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Other comments
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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. |
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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). |
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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+. |
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