Hemopexin

HPX
Identifiers
Aliases	HPX, HX, hemopexin
External IDs	OMIM: 142290 MGI: 105112 HomoloGene: 511 GeneCards: HPX
Gene location (Human)
Chr.	Chromosome 11 (human)
End	6,442,617 bp
Gene location (Mouse)
Chr.	Chromosome 7 (mouse)
End	105,249,344 bp
RNA expression pattern
	Top expressed in
	right lobe of liver; ; right uterine tube; ; right coronary artery; ; tibial nerve; ; minor salivary glands; ; body of pancreas; ; skin of abdomen; ; fundus; ; body of stomach; ; ascending aorta;
	Top expressed in
	left lobe of liver; ; gallbladder; ; right lobe of liver; ; pyloric antrum; ; sexually immature organism; ; morula; ; right lung lobe; ; abdominal wall; ; ureter; ; duodenum;
	More reference expression data
	; ;
	More reference expression data
Gene ontology
Molecular function	heme transmembrane transporter activity; protein binding; metal ion binding; metallopeptidase activity;
Cellular component	extracellular region; endocytic vesicle lumen; extracellular exosome; blood microparticle; extracellular space; collagen-containing extracellular matrix;
Biological process	regulation of protein metabolic process; positive regulation of immunoglobulin production; positive regulation of interferon-gamma-mediated signaling pathway; positive regulation of humoral immune response mediated by circulating immunoglobulin; viral process; positive regulation of response to interferon-gamma; receptor-mediated endocytosis; hemoglobin metabolic process; heme transport; cellular iron ion homeostasis; heme metabolic process; positive regulation of tyrosine phosphorylation of STAT protein; transport; proteolysis;
	Sources:Amigo / QuickGO
Orthologs
	3263
	15458
	ENSG00000110169
	ENSMUSG00000030895
	P02790
	Q91X72
	NM_000613
	NM_017371
	NP_000604
	NP_059067
	Wikidata
View/Edit Human	View/Edit Mouse

Hemopexin (or haemopexin; Hpx; Hx), also known as beta-1B-glycoprotein, is a glycoprotein that in humans is encoded by the HPX gene and belongs to the hemopexin family of proteins. Hemopexin is the plasma protein with the highest binding affinity for heme.

Hemoglobin itself circulating alone in the blood plasma (called free hemoglobin, as opposed to the hemoglobin situated in and circulating with the red blood cell.) will soon be oxidized into met-hemoglobin which then further disassociates into free heme along with globin chain. The free heme will then be oxidized into free met-heme and sooner or later the hemopexin will come to bind free met-heme together, forming a complex of met-heme and hemopexin, continuing their journey in the circulation until reaching a receptor, such as LRP1, on hepatocytes or macrophages within the spleen, liver and bone marrow.

Hemopexin's arrival and subsequent binding to the free heme not only prevent heme's pro-oxidant and pro-inflammatory effects but also promotes free heme's detoxification.

Hemopexin is different from haptoglobin, the latter always binds to free hemoglobin. (See Haptoglobin § Differentiation with hemopexin)

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