{PDOC00396}
{PS00460; GLUTATHIONE_PEROXID_1}
{PS00763; GLUTATHIONE_PEROXID_2}
{PS51355; GLUTATHIONE_PEROXID_3}
{BEGIN}
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* Glutathione peroxidases signatures and profile *
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Glutathione peroxidase (EC 1.11.1.9) (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) [3], a plasma secreted form (GSHPx-P) [4], and a epididymal secretory form
(GSHPx-EP). In  addition  to  these  characterized  forms,  the  sequence of a
protein of  unknown  function [5] 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 [6].

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 [7]. 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.


-Consensus pattern: [GNDRC]-[RKHNQFYCS]-x-[LIVMFCS]-[LIVMF](2)-x-N-[VT]-x-
                    [STCA]-x-[CU]-[GA]-x-[TA]
                    [C/U is the active site residue]
-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: [LIV]-[AGD]-F-P-[CS]-[NG]-Q-F
-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Last update: January 2008 / Pattern updated.

[ 1] Mannervik B.
     "Glutathione peroxidase."
     Methods Enzymol. 113:490-495(1985).
     PubMed=4088069
[ 2] Mullenbach G.T., Tabrizi A., Irvine B.D., Bell G.I., Tainer J.A.,
     Hallewell R.A.
     "Selenocysteine's mechanism of incorporation and evolution revealed in
     cDNAs of three glutathione peroxidases."
     Protein Eng. 2:239-246(1988).
     PubMed=2976939
[ 3] Chu F.F., Doroshow J.H., Esworthy R.S.
     "Expression, characterization, and tissue distribution of a new
     cellular selenium-dependent glutathione peroxidase, GSHPx-GI."
     J. Biol. Chem. 268:2571-2576(1993).
     PubMed=8428933
[ 4] Takahashi K., Akasaka M., Yamamoto Y., Kobayashi C., Mizoguchi J.,
     Koyama J.
     "Primary structure of human plasma glutathione peroxidase deduced from
     cDNA sequences."
     J. Biochem. 108:145-148(1990).
     PubMed=2229017
[ 5] Dunn D.K., Howells D.D., Richardson J.P., Goldfarb P.S.
     "A human cDNA sequence for a novel glutathione peroxidase-related
     selenopeptide, GPRP."
     Nucleic Acids Res. 17:6390-6390(1989).
     PubMed=2771650
[ 6] Cookson E., Blaxter M.L., Selkirk M.E.
     "Identification of the major soluble cuticular glycoprotein of
     lymphatic filarial nematode parasites (gp29) as a secretory homolog of
     glutathione peroxidase."
     Proc. Natl. Acad. Sci. U.S.A. 89:5837-5841(1992).
     PubMed=1631065
[ 7] Stadtman T.C.
     "Selenium biochemistry."
     Annu. Rev. Biochem. 59:111-127(1990).
     PubMed=2142875; DOI=10.1146/annurev.bi.59.070190.000551

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