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

Tong Shin Chang, Woojin Jeong, Hyun Ae Woo, Mi Lee Sun, Sunjoo Park, Goo Rhee Sue

Research output: Contribution to journalArticlepeer-review

302 Scopus citations

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.

Original languageEnglish
Pages (from-to)50994-51001
Number of pages8
JournalJournal of Biological Chemistry
Volume279
Issue number49
DOIs
StatePublished - 3 Dec 2004

Fingerprint

Dive into the research topics of 'Characterization of mammalian sulfiredoxin and its reactivation of hyperoxidized peroxiredoxin through reduction of cysteine sulfinic acid in the active site to cysteine'. Together they form a unique fingerprint.

Cite this