title: Peroxiredoxin 6, a 1-Cys peroxiredoxin, functions in antioxidant defense and lung phospholipid metabolism.
abstract: Peroxiredoxin 6 (Prdx6), a bifunctional 25-kDa protein with both GSH peroxidase and phospholipase A2 activities, is the only mammalian 1-Cys member of the peroxiredoxin superfamily and is expressed in all major organs, with a particularly high level in lung. Prdx6 uses GSH as an electron donor to reduce H2O2 and other hydroperoxides including phospholipid hydroperoxides at approximately 5 micromol/mg protein/min with K1 approximately 3 x 10(6) M(-1) s(-1). Oxidation of the Cys47 to a sulfenic acid during catalysis requires piGST-catalyzed glutathionylation and reduction with GSH to complete the enzymatic cycle. Prdx6 stably overexpressed in cells protected against oxidative stress, whereas antisense treatment resulted in oxidant stress and apoptosis. Adenoviral-mediated overexpression of Prdx6 in mouse lungs protected against the toxicity of hyperoxia, whereas Prdx6-null mice were more sensitive to the effects of hyperoxia or paraquat. We postulate that Prdx6 functions in antioxidant defense mainly by facilitating repair of damaged cell membranes via reduction of peroxidized phospholipids. The PLA2 activity of Prdx6 is Ca2+ independent and maximal at acidic pH. Inhibition of PLA2 activity results in alterations of lung surfactant phospholipid synthesis and turnover. Thus, Prdx6, a unique mammalian peroxiredoxin, is an important antioxidant enzyme and has a major role in lung phospholipid metabolism.
authors.affiliation: Institute for Environmental Medicine, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA.
authors.forename: Yefim
authors.initials: Y
authors.lastname: Manevich
authors.forename: Aron B
authors.initials: AB
authors.lastname: Fisher
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism; D017209:Apoptosis; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D004583:Electrons; D005978:Glutathione / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000378:metabolism; D007700:Kinetics; D008168:Lung / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008956:Models, Chemical; D008958:Models, Molecular; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010544:Peroxidases / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D010741:Phospholipases A / Q000737:chemistry; D054467:Phospholipases A2; D012333:RNA, Messenger / Q000378:metabolism; D013329:Structure-Activity Relationship; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; D010544:Peroxidases; C515977:PRDX6 protein, human; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; C515983:Prdx6 protein, mouse; D010741:Phospholipases A; D054467:Phospholipases A2; D005978:Glutathione; D010100:Oxygen; D002118:Calcium