|PROSITE documentation PDOC00396|
Glutathione peroxidase (EC 18.104.22.168) (GSHPx) [1,2] is an enzyme that catalyzes the reduction of hydroxyperoxides by glutathione. Its main function is to protect against the damaging effect of endogenously formed hydroxyperoxides.
In higher vertebrates at least four forms of GSHPx are known to exist: a ubiquitous cytosolic form (GSHPx-1), a gastrointestinal cytosolic for (GSHPx-GI) , a plasma secreted form (GSHPx-P) , and a epididymal secretory form (GSHPx-EP). In addition to these characterized forms, the sequence of a protein of unknown function  has been shown to be evolutionary related to those of GSHPx's.
In filarial nematode parasites such as Brugia pahangi the major soluble cuticular protein, known as gp29, is a secreted GSHPx which could provide a mechanism of resistance to the immune reaction of the mammalian host by neutralizing the products of the oxidative burst of leukocytes .
Escherichia coli protein btuE, a periplasmic protein involved in the transport of vitamin B12, is also evolutionary related to GSHPx's; the significance of this relationship is not yet clear.
The catalyic site of GSHPx contains a conserved residue which is either a cysteine or, in many eukaryotic GSHPx, a selenocysteine . The region around this active site residue can be used as a signature pattern. As a second signature for this family of proteins we selected a highly conserved octapeptide located in the central section of these proteins. We also developed a profile that covers the whole conserved region.Last update:
January 2008 / Pattern updated.
PROSITE methods (with tools and information) covered by this documentation:
|Source||Methods Enzymol. 113:490-495(1985).|
|2||Authors||Mullenbach G.T. Tabrizi A. Irvine B.D. Bell G.I. Tainer J.A. Hallewell R.A.|
|Title||Selenocysteine's mechanism of incorporation and evolution revealed in cDNAs of three glutathione peroxidases.|
|Source||Protein Eng. 2:239-246(1988).|
|3||Authors||Chu F.F. Doroshow J.H. Esworthy R.S.|
|Title||Expression, characterization, and tissue distribution of a new cellular selenium-dependent glutathione peroxidase, GSHPx-GI.|
|Source||J. Biol. Chem. 268:2571-2576(1993).|
|4||Authors||Takahashi K. Akasaka M. Yamamoto Y. Kobayashi C. Mizoguchi J. Koyama J.|
|Title||Primary structure of human plasma glutathione peroxidase deduced from cDNA sequences.|
|Source||J. Biochem. 108:145-148(1990).|
|5||Authors||Dunn D.K. Howells D.D. Richardson J.P. Goldfarb P.S.|
|Title||A human cDNA sequence for a novel glutathione peroxidase-related selenopeptide, GPRP.|
|Source||Nucleic Acids Res. 17:6390-6390(1989).|
|6||Authors||Cookson E. Blaxter M.L. Selkirk M.E.|
|Title||Identification of the major soluble cuticular glycoprotein of lymphatic filarial nematode parasites (gp29) as a secretory homolog of glutathione peroxidase.|
|Source||Proc. Natl. Acad. Sci. U.S.A. 89:5837-5841(1992).|
|Source||Annu. Rev. Biochem. 59:111-127(1990).|