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16  structures 1036  species 1  interaction 1200  sequences 7  architectures

# Summary: Urocanase

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This is the Wikipedia entry entitled "Urocanase". More...

# Urocanase

Urocanase
Crystal structure of Urocanase from B. subtilis.
Identifiers
Symbol Urocanase
Pfam PF01175
InterPro IPR000193
PROSITE PDOC00947

Urocanase[1] (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 coded for by the UROC1 gene, located on the 3rd chromosome in humans.[2] The protein itself is composed of 676 amino acids which then fold, producing the final product which has 2 identical subunits, making the enzyme a homodimer.

To catalyze the hydrolysis of urocanate in the catabolic pathway of L-histidine the enzyme utilizes it's two NAD+ (Nicotinamide Adnene Dinucleotide) groups. The NAD+ groups act as electrophiles, attaching to the top carbon of the urocanate which leads to sigmatropic rearrangement of the urocanate molecule.[3] This rearrangement allows for the addition of a water molecule, converting the urocanate into 4,5-dihydro-4-oxo-5-imidazolepropanoate.[4]

urocanate + H2O ${\displaystyle \rightleftharpoons }$ 4,5-dihydro-4-oxo-5-imidazolepropanoate

Inherited deficiency of urocanase leads to elevated levels of urocanic acid in the urine, a condition known as urocanic aciduria.

Urocanase is found in some bacteria (gene hutU), 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+.

## References

1. ^ Retey J (1994). "The urocanase story: a novel role of NAD+ as electrophile". Arch. Biochem. Biophys. 314 (1): 1–16. doi:10.1006/abbi.1994.1405. PMID 7944380.
2. ^ "http://www.genecards.org/cgi-bin/carddisp.pl?gene=UROC1". www.genecards.org. Retrieved 2016-11-03. External link in `|title=` (help)
3. ^ Kevin Tokoph (2014-12-23), Urocanate Hydratase Mechanism, retrieved 2016-11-03
4. ^

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

# Urocanase

No Pfam abstract.

## External database links

This tab holds annotation information from the InterPro database.

# InterPro entry IPR023637

Urocanase [PUBMED: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) [PUBMED: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 [PUBMED:15313616].

### Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

# Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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# Alignments

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## View options

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(157)
Full
(1200)
Representative proteomes UniProt
(5625)
NCBI
(9078)
Meta
(698)
RP15
(284)
RP35
(868)
RP55
(1646)
RP75
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## Format an alignment

Seed
(157)
Full
(1200)
Representative proteomes UniProt
(5625)
NCBI
(9078)
Meta
(698)
RP15
(284)
RP35
(868)
RP55
(1646)
RP75
(2704)
Alignment:
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Sequence:
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## Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

Seed
(157)
Full
(1200)
Representative proteomes UniProt
(5625)
NCBI
(9078)
Meta
(698)
RP15
(284)
RP35
(868)
RP55
(1646)
RP75
(2704)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download   Download   Download
Gzipped Download   Download   Download   Download   Download   Download   Download   Download   Download

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

# HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

# Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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# Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

## Curation

 Seed source: Prosite Previous IDs: none Type: Family Author: Finn RD, Bateman A Number in seed: 157 Number in full: 1200 Average length of the domain: 506.90 aa Average identity of full alignment: 48 % Average coverage of the sequence by the domain: 90.39 %

## HMM information

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 17690987 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 23.2 23.2
Trusted cut-off 26.4 23.3
Noise cut-off 21.1 22.4
Model length: 537
Family (HMM) version: 16
Download: download the raw HMM for this family

# Species distribution

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 Archea Eukaryota Bacteria Other sequences Viruses Unclassified Viroids Unclassified sequence

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# Interactions

There is 1 interaction for this family. More...

# Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Urocanase domain has been found. There are 16 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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