Apolipoprotein H

APOH
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	1C1Z, 1G4F, 1G4G, 1QUB, 2KRI, 3OP8, 4JHS
Identifiers
Aliases	APOH, B2G1, B2GP1, BG, apolipoprotein H
External IDs	OMIM: 138700; MGI: 88058; HomoloGene: 26; GeneCards: APOH; OMA:APOH - orthologs
Gene location (Human)
Chr.	Chromosome 17 (human)
End	66,256,525 bp
Gene location (Mouse)
Chr.	Chromosome 11 (mouse)
End	108,305,222 bp
RNA expression pattern
	Top expressed in
	liver; ; right lobe of liver; ; kidney tubule; ; testicle; ; islet of Langerhans; ; gonad; ; glomerulus; ; metanephric glomerulus; ; pancreatic epithelial cell; ; body of pancreas;
	Top expressed in
	left lobe of liver; ; gallbladder; ; fetal liver hematopoietic progenitor cell; ; spermatid; ; human fetus; ; seminiferous tubule; ; sexually immature organism; ; proximal tubule; ; spermatocyte; ; right kidney;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	heparin binding; lipoprotein lipase activator activity; protein binding; identical protein binding; phospholipid binding; lipid binding;
Cellular component	extracellular matrix; chylomicron; very-low-density lipoprotein particle; high-density lipoprotein particle; extracellular exosome; platelet dense granule lumen; extracellular space; cell surface; extracellular region; collagen-containing extracellular matrix;
Biological process	blood coagulation, intrinsic pathway; negative regulation of fibrinolysis; negative regulation of blood coagulation; positive regulation of lipoprotein lipase activity; negative regulation of endothelial cell migration; negative regulation of endothelial cell proliferation; positive regulation of blood coagulation; negative regulation of angiogenesis; triglyceride transport; plasminogen activation; regulation of blood coagulation; negative regulation of myeloid cell apoptotic process; regulation of fibrinolysis; triglyceride metabolic process; negative regulation of smooth muscle cell apoptotic process; platelet degranulation;
	Sources:Amigo / QuickGO
Orthologs
	350
	11818
	ENSG00000091583
	ENSMUSG00000000049
	P02749
	Q01339
	NM_000042
	NM_013475
	NP_000033
	NP_038503
	Wikidata
View/Edit Human	View/Edit Mouse

β₂-glycoprotein 1, also known as beta-2 glycoprotein 1 and Apolipoprotein H (Apo-H), is a 38 kDa multifunctional plasma protein that in humans is encoded by the APOH gene. One of its functions is to bind cardiolipin. When bound, the structure of cardiolipin and β₂-GP1 both undergo large changes in structure. Within the structure of Apo-H is a stretch of positively charged amino acids (protein sequence positions 282-287), Lys-Asn-Lys-Glu-Lys-Lys, are involved in phospholipid binding (see image on right).

β₂-GP1 has a complex involvement in agglutination. It appears to alter adenosine diphosphate (ADP)-mediated agglutination of platelets. Normally, β₂-GP1 assumes an anticoagulation activity in serum (by inhibiting coagulation factors); however, changes in blood factors can result in a reversal of that activity.

Although previously referred to as apolipoprotein H, it is not present in appreciable quantities in the lipoprotein fractions, so ApoH is therefore thought to be a misnomer.