Molecular function

GO:0033742, GO:0072561

methionine sulfoxide (protein) reductase activity, peptide-methionine-(S)-S-oxide reductase activity, protein-methionine-S-oxide reductase activity

Catalysis of the reactions: peptide-L-methionine + thioredoxin disulfide + H2O = peptide-L-methionine (S)-S-oxide + thioredoxin, and L-methionine + thioredoxin disulfide + H2O = L-methionine (S)-S-oxide + thioredoxin. Can act on oxidized methionine in peptide linkage with specificity for the S enantiomer. Thioredoxin disulfide is the oxidized form of thioredoxin.

MsrA, methionine S-oxide reductase (S-form oxidizing) activity, methionine sulfoxide reductase A activity, methionine sulphoxide reductase A activity, peptide Met(O) reductase activity, peptide methionine sulfoxide reductase activity, peptide-L-methionine:thioredoxin-disulfide S-oxidoreductase [L-methionine (S)-S-oxide-forming] activity