Histidine decarboxylase

Histidine decarboxylase
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 4E1O
Identifiers
Symbols	HDC ; MGC163399
External IDs	OMIM: 142704 MGI: 96062 HomoloGene: 20490 IUPHAR: 1274 GeneCards: HDC Gene
EC number	4.1.1.22
Gene ontology Molecular function • histidine decarboxylase activity • protein binding • pyridoxal phosphate binding Cellular component • cytosol Biological process • histamine biosynthetic process • histidine metabolic process • histidine catabolic process • cellular nitrogen compound metabolic process • catecholamine biosynthetic process • small molecule metabolic process Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	3067	15186
Ensembl	ENSG00000140287	ENSMUSG00000027360
UniProt	P19113	P23738
RefSeq (mRNA)	NM_001306146	NM_008230
RefSeq (protein)	NP_001293075	NP_032256
Location (UCSC)	Chr 15: 50.24 – 50.27 Mb	Chr 2: 126.59 – 126.62 Mb
PubMed search	[1]	[2]

histidine decarboxylase
Identifiers
EC number	4.1.1.22
CAS number	Template:CAS
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles NCBI proteins

Histidine carboxylase PI chain
structure of the d53,54n mutant of histidine decarboxylase at-170 c
Identifiers
Symbol	HDC
Pfam	PF02329
InterPro	IPR003427
SCOP	1pya
SUPERFAMILY	1pya
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Histidine decarboxylase (HDC) is the enzyme that catalyzes the reaction that produces histamine from histidine with the help of vitamin B₆ as follows:

Conversion of histidine to histamine by histidine decarboxylase

In humans, the histidine decarboxylase enzyme is encoded by the HDC gene.

Function

The biogenic amine histamine is an important modulator of numerous physiologic processes, including neurotransmission, gastric acid secretion, and smooth muscle tone. The biosynthesis of histamine from histidine is catalyzed by the enzyme L-histidine decarboxylase. This homodimeric enzyme is a pyridoxal phosphate (PLP)-dependent decarboxylase and is highly specific for its histidine substrate.

Biosynthesis

In bacteria, it is synthesised as a proenzyme, PI. Cleavage of the proenzyme PI chain yields two subunits, alpha and beta, which arrange as a hexamer, (alpha beta)6, by nonhydrolytic self-catalysis.

Clinical significance

Inhibitors of histidine decarboxylase can be used as atypical antihistamines. (See Tritoqualine)

Mutations in the gene for this enzyme have been observed in one family with Tourette syndrome (TS) and are not thought to account for most cases of TS.

See also

• Aromatic L-amino acid decarboxylase

External links

• Histidine Decarboxylase at the US National Library of Medicine Medical Subject Headings (MeSH)

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