ID 1.11.1.27 DE glutathione-dependent peroxiredoxin. CA a hydroperoxide + 2 glutathione = an alcohol + glutathione disulfide + CA H2O. CC -!- Peroxiredoxins (Prxs) are a ubiquitous family of antioxidant CC proteins. CC -!- They can be divided into three classes: typical 2-Cys, atypical 2-Cys CC and 1-Cys peroxiredoxins. CC -!- The peroxidase reaction comprises two steps centered around a redox- CC active cysteine called the peroxidatic cysteine. CC -!- All three peroxiredoxin classes have the first step in common, CC in which the peroxidatic cysteine attacks the peroxide substrate and CC is oxidized to S-hydroxycysteine (a sulfenic acid). CC -!- The second step of the peroxidase reaction, the regeneration of CC cysteine from S-hydroxycysteine, distinguishes the three CC peroxiredoxin classes. CC -!- For typical 2-Cys Prxs, in the second step, the peroxidatic CC S-hydroxycysteine from one subunit is attacked by the 'resolving' CC cysteine located in the C-terminus of the second subunit, to form an CC intersubunit disulfide bond, which is then reduced by one of several CC cell-specific thiol-containing reductants completing the catalytic CC cycle. CC -!- In the atypical 2-Cys Prxs, both the peroxidatic cysteine and its CC resolving cysteine are in the same polypeptide, so their reaction CC forms an intrachain disulfide bond. CC -!- The 1-Cys Prxs conserve only the peroxidatic cysteine, so its CC regeneration involves direct interaction with a reductant molecule. CC -!- Glutathione-dependent peroxiredoxins have been reported from bacteria CC and animals, and appear to be 1-Cys enzymes. CC -!- The mechanism for the mammalian PRDX6 enzyme involves CC heterodimerization of the enzyme with pi-glutathione S-transferase, CC followed by glutathionylation of the oxidized cysteine residue. CC -!- Subsequent dissociation of the heterodimer yields glutathionylated CC peroxiredoxin, which is restored to the active form via spontaneous CC reduction by a second glutathione molecule. CC -!- Formerly EC 1.11.1.15. DR P00450, CERU_HUMAN ; Q61147, CERU_MOUSE ; P13635, CERU_RAT ; DR Q9XT27, CERU_SHEEP ; O77834, PRDX6_BOVIN; Q5ZJF4, PRDX6_CHICK; DR P30041, PRDX6_HUMAN; Q2PFL9, PRDX6_MACFA; P86215, PRDX6_MESAU; DR O08709, PRDX6_MOUSE; Q9TSX9, PRDX6_PIG ; Q5R7E0, PRDX6_PONAB; DR O35244, PRDX6_RAT ; P34227, PRX1_YEAST ; P44758, PRX5_HAEIN ; DR O69777, PRX5_RHIET ; Q53212, PRX5_SINFN ; P73728, PRX5_SYNY3 ; //