Histidine ammonia-lyase

From Wikipedia, the free encyclopedia
  (Redirected from Histidase)
Jump to: navigation, search
Histidine ammonia-lyase
Symbols HAL ; HIS; HSTD
External IDs OMIM609457 MGI96010 HomoloGene68229 ChEMBL: 4003 GeneCards: HAL Gene
EC number
Species Human Mouse
Entrez 3034 15109
Ensembl ENSG00000084110 ENSMUSG00000020017
UniProt P42357 P35492
RefSeq (mRNA) NM_001258333 NM_010401
RefSeq (protein) NP_001245262 NP_034531
Location (UCSC) Chr 12:
95.97 – 96 Mb
Chr 10:
93.49 – 93.52 Mb
PubMed search [1] [2]
histidine ammonia-lyase
EC number
CAS number 9013-75-6
IntEnz IntEnz view
ExPASy NiceZyme view
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO

Histidine ammonia-lyase (or histidase, or histidinase) is an enzyme that in humans is encoded by the HAL gene.[1][2] Histidase converts histidine into ammonia and urocanic acid.


Histidine ammonia-lyase is a cytosolic enzyme catalyzing the first reaction in histidine catabolism, the nonoxidative deamination of L-histidine to trans-urocanic acid.[1] The reaction is catalyzed by an electrophilic co-factor which is formed autocatalytically by cyclization of the protein backbone of the enzyme.[3]


Mutations in the gene for histidase are associated with histidinemia and urocanic aciduria.

Further reading[edit]


  1. ^ a b "Entrez Gene: histidine ammonia-lyase". 
  2. ^ Suchi M, Sano H, Mizuno H, Wada Y (September 1995). "Molecular cloning and structural characterization of the human histidase gene (HAL)". Genomics 29 (1): 98–104. doi:10.1006/geno.1995.1219. PMID 8530107. 
  3. ^ Schwede, TF; Rétey, J; Schulz, GE (Apr 27, 1999). "Crystal structure of histidine ammonia-lyase revealing a novel polypeptide modification as the catalytic electrophile.". Biochemistry 38 (17): 5355–5361. doi:10.1021/bi982929q. PMID 10220322. 

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.