Eosinophil peroxidase is a haloperoxidaseenzyme that in humans is encoded by the EPXgene. The enzyme is a heterodimeric 71-77 kD peroxidase consisting of a heavier glycosylated chain and a lighter nonglycosylated chain. This enzyme prefers bromide over chloride as a substrate, converting it to toxic hypobromite.
In the presence of H2O2 formed by the eosinophil, and either chloride or bromide ions, eosinophil peroxidase provides a potent mechanism by which eosinophils kill multicellular parasites (such as, for example, the nematode worms involved in filariasis); and also certain bacteria (such as tuberculosis bacteria). Eosinophil peroxidase is a haloperoxidase that preferentially uses bromide over chloride for this purpose, generating hypobromite (hypobromous acid). The enzyme is also capable of oxidizing thiocyanate (SCN-) and uses it as a co-substrate, with optimal concentrations occurring at about normal plasma levels.
Eosinophil peroxidase is also partly responsible for tissue remodeling.
^Sakamaki K, Tomonaga M, Tsukui K, Nagata S (October 1989). "Molecular cloning and characterization of a chromosomal gene for human eosinophil peroxidase". J. Biol. Chem.264 (28): 16828–36. PMID2550461.
Sakamaki K, Tomonaga M, Tsukui K, Nagata S (1989). "Molecular cloning and characterization of a chromosomal gene for human eosinophil peroxidase". J. Biol. Chem.264 (28): 16828–36. PMID2550461.
Nakamura H, Miyagawa K, Ogino K, et al. (2003). "High contribution contrast between the genes of eosinophil peroxidase and IL-4 receptor alpha-chain in Japanese cedar pollinosis". J. Allergy Clin. Immunol.112 (6): 1127–31. doi:10.1016/j.jaci.2003.08.051. PMID14657871.
Hrdlickova B, Izakovicova-Holla L (2009). "Association of single nucleotide polymorphisms in the eosinophil peroxidase gene with allergic rhinitis in the Czech population". Int. Arch. Allergy Immunol.150 (2): 184–91. doi:10.1159/000218122. PMID19439985.
Nakamura H, Higashikawa F, Miyagawa K, et al. (2004). "Association of single nucleotide polymorphisms in the eosinophil peroxidase gene with Japanese cedar pollinosis". Int. Arch. Allergy Immunol.135 (1): 40–3. doi:10.1159/000080222. PMID15316147.
Sakamaki K, Kanda N, Ueda T, et al. (2000). "The eosinophil peroxidase gene forms a cluster with the genes for myeloperoxidase and lactoperoxidase on human chromosome 17". Cytogenet. Cell Genet.88 (3–4): 246–8. doi:10.1159/000015529. PMID10828600.
Wu C, Ma MH, Brown KR, et al. (2007). "Systematic identification of SH3 domain-mediated human protein-protein interactions by peptide array target screening". Proteomics7 (11): 1775–85. doi:10.1002/pmic.200601006. PMID17474147.
Oxvig C, Thomsen AR, Overgaard MT, et al. (1999). "Biochemical evidence for heme linkage through esters with Asp-93 and Glu-241 in human eosinophil peroxidase. The ester with Asp-93 is only partially formed in vivo". J. Biol. Chem.274 (24): 16953–8. doi:10.1074/jbc.274.24.16953. PMID10358043.