[cite web | title = Entrez Gene: HPX hemopexin| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=3263| accessdate = ] ]The protein encoded by this gene, hemopexin (or haemopexin) binds heme with the highest affinity of any known protein. Its function of scavenging the heme released or lost by the turnover of heme proteins such as hemoglobin 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. Low levels indicate that there is a lot of it. Therefore, low hemopexin levels indicates that there has been significant degradation of heme containing compounds - the latter being primarily hemoglobin, it indicates hemolysis and low hemopexin levels are therefore one of the diagnostic features of a hemolytic anemia.
References
Further reading
PBB_Further_reading
citations =
*cite journal | author=Piccard H, Van den Steen PE, Opdenakker G |title=Hemopexin domains as multifunctional liganding modules in matrix metalloproteinases and other proteins. |journal=J. Leukoc. Biol. |volume=81 |issue= 4 |pages= 870–92 |year= 2007 |pmid= 17185359 |doi= 10.1189/jlb.1006629
*cite journal | author=Morgan WT, Muller-Eberhard U, Lamola AA |title=Interaction of rabbit hemopexin with bilirubin. |journal=Biochim. Biophys. Acta |volume=532 |issue= 1 |pages= 57–64 |year= 1978 |pmid= 620056 |doi=
*cite journal | author=Liu HM, Atack JR, Rapoport SI |title=Immunohistochemical localization of intracellular plasma proteins in the human central nervous system. |journal=Acta Neuropathol. |volume=78 |issue= 1 |pages= 16–21 |year= 1989 |pmid= 2735186 |doi=
*cite journal | author=Smith A, Tatum FM, Muster P, "et al." |title=Importance of ligand-induced conformational changes in hemopexin for receptor-mediated heme transport. |journal=J. Biol. Chem. |volume=263 |issue= 11 |pages= 5224–9 |year= 1988 |pmid= 2833500 |doi=
*cite journal | author=Altruda F, Poli V, Restagno G, Silengo L |title=Structure of the human hemopexin gene and evidence for intron-mediated evolution. |journal=J. Mol. Evol. |volume=27 |issue= 2 |pages= 102–8 |year= 1988 |pmid= 2842511 |doi=
*cite journal | author=Altruda F, Poli V, Restagno G, "et al." |title=The primary structure of human hemopexin deduced from cDNA sequence: evidence for internal, repeating homology. |journal=Nucleic Acids Res. |volume=13 |issue= 11 |pages= 3841–59 |year= 1985 |pmid= 2989777 |doi=
*cite journal | author=Taketani S, Kohno H, Naitoh Y, Tokunaga R |title=Isolation of the hemopexin receptor from human placenta. |journal=J. Biol. Chem. |volume=262 |issue= 18 |pages= 8668–71 |year= 1987 |pmid= 3036819 |doi=
*cite journal | author=Law ML, Cai GY, Hartz JA, "et al." |title=The hemopexin gene maps to the same location as the beta-globin gene cluster on human chromosome 11. |journal=Genomics |volume=3 |issue= 1 |pages= 48–52 |year= 1989 |pmid= 3220477 |doi=
*cite journal | author=Morgan WT, Alam J, Deaciuc V, "et al." |title=Interaction of hemopexin with Sn-protoporphyrin IX, an inhibitor of heme oxygenase. Role for hemopexin in hepatic uptake of Sn-protoporphyrin IX and induction of mRNA for heme oxygenase. |journal=J. Biol. Chem. |volume=263 |issue= 17 |pages= 8226–31 |year= 1988 |pmid= 3372522 |doi=
*cite journal | author=Takahashi N, Takahashi Y, Putnam FW |title=Complete amino acid sequence of human hemopexin, the heme-binding protein of serum. |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=82 |issue= 1 |pages= 73–7 |year= 1985 |pmid= 3855550 |doi=
*cite journal | author=Takahashi N, Takahashi Y, Putnam FW |title=Structure of human hemopexin: O-glycosyl and N-glycosyl sites and unusual clustering of tryptophan residues. |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=81 |issue= 7 |pages= 2021–5 |year= 1984 |pmid= 6371807 |doi=
*cite journal | author=Frantíková V, Borvák J, Kluh I, Morávek L |title=Amino acid sequence of the N-terminal region of human hemopexin. |journal=FEBS Lett. |volume=178 |issue= 2 |pages= 213–6 |year= 1985 |pmid= 6510521 |doi=
*cite journal | author=Smith A, Alam J, Escriba PV, Morgan WT |title=Regulation of heme oxygenase and metallothionein gene expression by the heme analogs, cobalt-, and tin-protoporphyrin. |journal=J. Biol. Chem. |volume=268 |issue= 10 |pages= 7365–71 |year= 1993 |pmid= 8463269 |doi=
*cite journal | author=Morris CM, Candy JM, Edwardson JA, "et al." |title=Evidence for the localization of haemopexin immunoreactivity in neurones in the human brain. |journal=Neurosci. Lett. |volume=149 |issue= 2 |pages= 141–4 |year= 1993 |pmid= 8474687 |doi=
*cite journal | author=Hrkal Z, Kuzelová K, Muller-Eberhard U, Stern R |title=Hyaluronan-binding properties of human serum hemopexin. |journal=FEBS Lett. |volume=383 |issue= 1-2 |pages= 72–4 |year= 1996 |pmid= 8612795 |doi=
*cite journal | author=Hunt RC, Hunt DM, Gaur N, Smith A |title=Hemopexin in the human retina: protection of the retina against heme-mediated toxicity. |journal=J. Cell. Physiol. |volume=168 |issue= 1 |pages= 71–80 |year= 1996 |pmid= 8647924 |doi= 10.1002/(SICI)1097-4652(199607)168:1<71::AID-JCP9>3.0.CO;2-5
*cite journal | author=Miller YI, Smith A, Morgan WT, Shaklai N |title=Role of hemopexin in protection of low-density lipoprotein against hemoglobin-induced oxidation. |journal=Biochemistry |volume=35 |issue= 40 |pages= 13112–7 |year= 1996 |pmid= 8855948 |doi= 10.1021/bi960737u
*cite journal | author=Grinberg LN, O'Brien PJ, Hrkal Z |title=The effects of heme-binding proteins on the peroxidative and catalatic activities of hemin. |journal=Free Radic. Biol. Med. |volume=27 |issue= 1-2 |pages= 214–9 |year= 1999 |pmid= 10443938 |doi=
*cite journal | author=Nakajima S, Moriyama T, Hayashi H, "et al." |title=Hemopexin as a carrier protein of tumor-localizing Ga-metalloporphyrin-ATN-2. |journal=Cancer Lett. |volume=149 |issue= 1-2 |pages= 221–6 |year= 2000 |pmid= 10737728 |doi=
*cite journal | author=Shipulina N, Smith A, Morgan WT |title=Heme binding by hemopexin: evidence for multiple modes of binding and functional implications. |journal=J. Protein Chem. |volume=19 |issue= 3 |pages= 239–48 |year= 2001 |pmid= 10981817 |doi=
External links
*
*
* [http://www.liebertonline.com/doi/abs/10.1089/104454902753759717 Hemopexin: Structure, Function, and Regulation]
* [http://sbs.umkc.edu/people/faculty/docMorganW.cfm William T. Morgan's Lab, studies Hemopexin]
* [http://library.med.utah.edu/NetBiochem/hi7a.htm Hemoglobin Info from library.med.utah.edu]
* [http://www.m-w.com/dictionary/haem Definition of Haem] = chiefly British variant of "heme"
=See also=
*Haptoglobin
*Hemoglobin
*Heme
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