In enzymology, a L-methionine (S)-S-oxide reductase (EC 220.127.116.11) is an enzyme that catalyzes the chemical reaction
The 3 substrates of this enzyme are L-methionine, thioredoxin disulfide, and H2O, whereas its two products are L-methionine (S)-S-oxide and thioredoxin.
This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with a disulfide as acceptor. The systematic name of this enzyme class is L-methionine:thioredoxin-disulfide S-oxidoreductase. Other names in common use include fSMsr, methyl sulfoxide reductase I and II, acetylmethionine sulfoxide reductase, methionine sulfoxide reductase, L-methionine:oxidized-thioredoxin S-oxidoreductase, methionine-S-oxide reductase, and free-methionine (S)-S-oxide reductase. This enzyme participates in methionine metabolism.