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Overoxidized peroxiredoxin VI (Prdx6) loses peroxidase activity but retains the ability to bind phospholipid hydroperoxides and phospholipase A2 (PLA2) activity.
Author(s) -
Manevich Yefim,
Shuvaeva Tea,
Fisher Aron B.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a89-a
Subject(s) - chemistry , peroxidase , phospholipase a2 , liposome , phospholipid , substrate (aquarium) , biochemistry , antioxidant , enzyme , biophysics , membrane , biology , ecology
Prdx6 differs from other mammalian peroxiredoxins by reducing phospholipid hydroperoxides and in having PLA 2 activity. Oxidation of its catalytic Cys47 inactivates the peroxidase function but effect on the PLA 2 activity is unknown. Incubation of recombinant Prdx6 with 1‐palmitoyl‐2‐linolenoyl‐ sn ‐glycero‐3‐phosphocholine hydroperoxide (PLPCOOH) resulted in Cys47 oxidation as detected by western blot with Prdx6‐SO 2(3) antibody and MS analysis. Oxidation kinetics of Cys47 with PLPCOOH and H 2 O 2 was similar. Denaturation of Prdx6 abolished PLPCOOH‐mediated oxidation. Thus, PLPCOOH is a specific substrate for Prdx6 peroxidase function and is also a substrate for Prdx6 PLA 2 activity. Prdx6 binding at pH 7 to DNS‐PE‐labeled oxidized liposomes was detected by changes in DNS fluorescence. Binding was similar for reduced or oxidized Prdx6 but was not observed with non‐oxidized liposomes. Preincubation of Prdx6 with 20μM mercaptosuccinate abolished peroxidase activity but had no effect on binding of Prdx6 to oxidized liposomes. Preincubation of Prdx6 with equimolar amount of the PLA 2 competitive inhibitor MJ33 diminished both PLPCOOH binding and reduction. Thus, binding of Prdx6 to oxidized phospholipids results in either peroxidase or PLA 2 catalysis depending on oxidation state of Cys47 which suggests synergy of these activities in the antioxidant function of the protein. Supported by HL065543.