Hemopexin

This article is about the hemopexin protein. For the family of proteins containing hemopexin-like repeats, see hemopexin family.

Hemopexin
Identifiers
Symbols	HPX ; HX
External IDs	OMIM: 142290 MGI: 105112 HomoloGene: 511 GeneCards: HPX Gene
EC number	3.2.1.35
Gene ontology Molecular function • protein binding • heme transporter activity • metal ion binding Cellular component • extracellular region • extracellular space • extracellular exosome • endocytic vesicle lumen • blood microparticle Biological process • positive regulation of immunoglobulin production • positive regulation of humoral immune response mediated by circulating immunoglobulin • cellular iron ion homeostasis • receptor-mediated endocytosis • heme transport • viral process • hemoglobin metabolic process • heme metabolic process • positive regulation of tyrosine phosphorylation of Stat1 protein • positive regulation of interferon-gamma-mediated signaling pathway Sources: Amigo / QuickGO
RNA expression pattern
File:PBB GE HPX 39763 at tn.png
File:PBB GE HPX 210013 at tn.png
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	3263	15458
Ensembl	ENSG00000110169	ENSMUSG00000030895
UniProt	P02790	Q91X72
RefSeq (mRNA)	NM_000613	NM_017371
RefSeq (protein)	NP_000604	NP_059067
Location (UCSC)	Chr 11: 6.43 – 6.44 Mb	Chr 7: 105.59 – 105.6 Mb
PubMed search	[1]	[2]

Hemopexin (or haemopexin; HPX), also known as beta-1B-glycoprotein is a protein that in humans is encoded by the HPX gene and belongs to hemopexin family of proteins.

Function

Hemopexin binds heme with the highest affinity of any known protein. Its function is scavenging the heme released or lost by the turnover of heme proteins such as hemoglobin and thus protects the body from the oxidative damage that free heme can cause. In addition, hemopexin releases its bound ligand for internalisation upon interacting with a specific receptor situated on the surface of liver cells. This function of hemopexin is to preserve the body's iron.

Clinical significance

Its levels in serum reflect how much heme is present in the blood. Therefore, low hemopexin levels indicates that there has been significant degradation of heme containing compounds and hemopexin is made to scavenge any heme it can. Low hemopexin levels are one of the diagnostic features of an intravascular hemolytic anemia.

External links

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

See also

• Haptoglobin
• Hemoglobin
• Heme