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Characterization of mammalian sulfiredoxin and its reactivation of hyperoxidized peroxiredoxin through reduction of cysteine sulfinic acid in the active site to cysteine

Title
Characterization of mammalian sulfiredoxin and its reactivation of hyperoxidized peroxiredoxin through reduction of cysteine sulfinic acid in the active site to cysteine
Authors
Chang T.-S.Jeong W.Hyun A.W.Sun M.L.Park S.Sue G.R.
Ewha Authors
이서구정우진창동신우현애
SCOPUS Author ID
이서구scopusscopus; 정우진scopus; 창동신scopus; 우현애scopus
Issue Date
2004
Journal Title
Journal of Biological Chemistry
ISSN
0021-9258JCR Link
Citation
Journal of Biological Chemistry vol. 279, no. 49, pp. 50994 - 51001
Indexed
SCIE; SCOPUS WOS scopus
Document Type
Article
Abstract
Peroxiredoxins (Prxs) are a family of peroxidases that reduce hydroperoxides. The cysteine residue in the active site of certain eukaryotic Prx enzymes undergoes reversible oxidation to sulfinic acid (Cys-SO 2H) during catalysis, and sulfiredoxin (Srx) has been identified as responsible for reversal of the resulting enzyme inactivation in yeast. We have now characterized mammalian orthologs of yeast Srx with an assay based on monitoring of the reduction of sulfinic Prx by immunoblot analysis with antibodies specific for the sulfinic state. Sulfinic reduction by mammalian Srx was found to be a slow process (kcat = 0.18/min) that requires ATP hydrolysis. ATP could be efficiently replaced by GTP, dATP, or dGTP but not by CTP, UTP, dCTP, or dTTP. Both glutathione and thioredoxin are potential physiological electron donors for the Srx reaction, given that their K m values (1.8 mM and 1.2 μM, respectively) are in the range of their intracellular concentrations, and the Vmax values obtained with the two reductants were similar. Although its pKa is relatively low (∼7.3), the active site cysteine of Srx remained reduced even when the active site cysteine of most Prx molecules became oxidized. Finally, depletion of human Srx by RNA interference suggested that Srx is largely responsible for reduction of the Cys-SO2H of Prx in A549 human cells.
DOI
10.1074/jbc.M409482200
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일반대학원 > 생명·약학부 > Journal papers
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