Analyses of methionine sulfoxide reductase activities towards free and peptidyl methionine sulfoxides

Geun Hee Kwak, Kwang Yeon Hwang, Hwa Young Kim

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

There have been insufficient kinetic data that enable a direct comparison between free and peptide methionine sulfoxide reductase activities of either MsrB or MsrA. In this study, we determined the kinetic parameters of mammalian and yeast MsrBs and MsrAs for the reduction of both free methionine sulfoxide (Met-O) and peptidyl Met-O under the same assay conditions. Catalytic efficiency of mammalian and yeast MsrBs towards free Met-O was >2000-fold lower than that of yeast fRMsr, which is specific for free Met-R-O. The ratio of free to peptide Msr activity in MsrBs was 1:20-40. In contrast, mammalian and yeast MsrAs reduced free Met-O much more efficiently than MsrBs. Their kcat values were 40-500-fold greater than those of the corresponding MsrBs. The ratio of free to peptide Msr activity was 1:0.8 in yeast MsrA, indicating that this enzyme can reduce free Met-O as efficiently as peptidyl Met-O. In addition, we analyzed the in vivo free Msr activities of MsrBs and MsrAs in yeast cells using a growth complementation assay. Mammalian and yeast MsrBs, as well as the corresponding MsrAs, had apparent in vivo free Msr activities. The in vivo free Msr activities of MsrBs and MsrAs agreed with their in vitro activities.

Original languageEnglish
Pages (from-to)1-5
Number of pages5
JournalArchives of Biochemistry and Biophysics
Volume527
Issue number1
DOIs
Publication statusPublished - 2012 Nov 1

Keywords

  • Free Msr activity
  • Growth complementation
  • Kinetic analysis
  • Methionine sulfoxide reductase
  • MsrA
  • MsrB

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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