. "Unlike EC 1.8.4.12 this enzyme cannot use peptide-bound methionine (R)-S-oxide as a substrate." . "Differs from EC 1.8.4.13, in that L-methionine (S)-S-oxide is not a substrate." . . . "FRMsr" . "L-methionine (R)-S-oxide reductase" . "Free met-R-(o) reductase" . "Free-methionine (R)-S-oxide reductase" . . "L-methionine + thioredoxin disulfide + H(2)O = L-methionine (R)-S-oxide + thioredoxin." . "NADPH" .