peptide-methionine (S)-S-oxide reductase activity

Definition

Target type: molecularfunction

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. [EC:1.8.4.11, GOC:mah, GOC:vw, PMID:11169920]

Peptide-methionine (S)-S-oxide reductase activity is an enzymatic function involved in the reduction of methionine sulfoxide residues in proteins. Methionine sulfoxide residues can be formed as a result of oxidative stress, and their accumulation can lead to protein misfolding and aggregation. Peptide-methionine (S)-S-oxide reductase activity plays a crucial role in repairing these damaged proteins and restoring their proper structure and function.

This activity is catalyzed by enzymes known as methionine sulfoxide reductases (Msrs). Msrs are a family of enzymes that specifically reduce methionine sulfoxide residues to methionine. There are two main types of Msrs: MsrA and MsrB. MsrA reduces methionine sulfoxide residues in the (S)-configuration, while MsrB reduces methionine sulfoxide residues in the (R)-configuration.

The mechanism of action of Msrs involves the transfer of electrons from a reduced cofactor, typically NADPH, to the methionine sulfoxide residue. This electron transfer results in the reduction of the sulfoxide group to a sulfide group, regenerating the methionine residue.

The specific molecular function of peptide-methionine (S)-S-oxide reductase activity is to catalyze the reduction of methionine sulfoxide residues in the (S)-configuration. This activity is essential for maintaining protein homeostasis and protecting cells from oxidative damage. MsrA is a major enzyme responsible for this activity and plays a crucial role in a variety of cellular processes, including protein repair, antioxidant defense, and signal transduction.

Overall, peptide-methionine (S)-S-oxide reductase activity is a vital enzymatic function that contributes to the maintenance of protein integrity and cellular function in the face of oxidative stress.'
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Proteins (1)

Compounds (1)