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Hydroperoxide reduction by thioredoxin‐specific glutathione peroxidase isoenzymes of Arabidopsis thaliana
Author(s) -
Iqbal Aqib,
Yabuta Yukinori,
Takeda Toru,
Nakano Yoshihisa,
Shigeoka Shigeru
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05548.x
Subject(s) - cumene hydroperoxide , thioredoxin , glutaredoxin , biochemistry , glutathione , peroxidase , chemistry , isozyme , thioredoxin reductase , gpx1 , arabidopsis thaliana , recombinant dna , gpx3 , glutathione peroxidase , microbiology and biotechnology , biology , enzyme , gene , mutant , catalysis
Arabidopsis thaliana contains eight glutathione peroxidase (GPX) homologs (AtGPX1–8). Four mature GPX isoenzymes with different subcellular distributions, AtGPX1, ‐2, ‐5 and ‐6, were overexpressed in Escherichia coli and characterized. Interestingly, these recombinant proteins were able to reduce H 2 O 2 , cumene hydroperoxide, phosphatidylcholine and linoleic acid hydroperoxides using thioredoxin but not glutathione or NADPH as an electron donor. The reduction activities of the recombinant proteins with H 2 O 2 were 2–7 times higher than those with cumene hydroperoxide. K m values for thioredoxin and H 2 O 2 were 2.2–4.0 and 14.0–25.4 µ m , respectively. These finding suggest that GPX isoenzymes may function to detoxify H 2 O 2 and organic hydroperoxides using thioredoxin in vivo and may also be involved in regulation of the cellular redox homeostasis by maintaining the thiol/disulfide or NADPH/NADP balance.