Haptoglobin

HP
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesHP, BP, HP2ALPHA2, HPA1S, haptoglobin
External IDsOMIM: 140100; MGI: 96211; HomoloGene: 121756; GeneCards: HP; OMA:HP - orthologs
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_001126102
NM_005143
NM_001318138

NM_017370
NM_001329965

RefSeq (protein)

NP_001119574
NP_001305067
NP_005134

NP_001316894
NP_059066

Location (UCSC)Chr 16: 72.05 – 72.06 MbChr 8: 110.3 – 110.31 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse
A model of α,β-hemoglobin/haptoglobin hexamer complex. There are 2 α,β-hemoglobin dimers depicted: one space filling model (yellow/orange), and one ribbon model (purple/blue). Each is bound by a haptoglobin molecule (both haptoglobin molecules are shown in pink, with one as a space filling model and one as a ribbon model).

Haptoglobin (abbreviated as Hp) is the protein that in humans is encoded by the HP gene.[5][6] In blood plasma, haptoglobin binds with high affinity to free hemoglobin[7] released from erythrocytes, and thereby inhibits its deleterious oxidative activity. Compared to Hp, hemopexin binds to free heme.[8] The haptoglobin-hemoglobin complex will then be removed by the reticuloendothelial system (mostly the spleen).

In clinical settings, the haptoglobin assay is used to screen for and monitor intravascular hemolytic anemia. In intravascular hemolysis, free hemoglobin will be released into circulation and hence haptoglobin will bind the hemoglobin. This causes a decline in haptoglobin levels.

The protein was discovered as a "plasma substance" in 1938 by French biochemists Max-Fernand Jayle and Michel Polonovski.[9][10]

  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000257017Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000031722Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Dobryszycka W (September 1997). "Biological functions of haptoglobin--new pieces to an old puzzle". European Journal of Clinical Chemistry and Clinical Biochemistry. 35 (9): 647–654. PMID 9352226.
  6. ^ Wassell J (2000). "Haptoglobin: function and polymorphism". Clinical Laboratory. 46 (11–12): 547–552. PMID 11109501.
  7. ^ Schaer DJ, Vinchi F, Ingoglia G, Tolosano E, Buehler PW (28 October 2014). "Haptoglobin, hemopexin, and related defense pathways-basic science, clinical perspectives, and drug development". Frontiers in Physiology. 5. Frontiers Media SA: 415. doi:10.3389/fphys.2014.00415. PMC 4211382. PMID 25389409.
  8. ^ Cite error: The named reference eClinpath was invoked but never defined (see the help page).
  9. ^ Shih AW, McFarlane A, Verhovsek M (April 2014). "Haptoglobin testing in hemolysis: measurement and interpretation". American Journal of Hematology. 89 (4): 443–447. doi:10.1002/ajh.23623. PMID 24809098.
  10. ^ "Haptoglobins". New England Journal of Medicine. 266 (11): 569–570. 15 March 1962. doi:10.1056/NEJM196203152661115. ISSN 0028-4793.