Methionine sulfoxide reductase B (MsrB)

Methionine sulfoxide reductase B (MsrB) is a vital antioxidant enzyme that facilitates the stereospecific reduction of methionine-R-sulfoxide residues in proteins back to methionine [UniProt, PMID: 23024004]. This enzymatic activity is crucial for the repair of oxidatively damaged proteins, thereby maintaining cellular proteostasis and protecting against oxidative stress [PubMed, PMID: 15610722]. In humans, the MsrB family includes three distinct isoforms: MsrB1 (a selenoprotein found in the cytosol and nucleus), MsrB2 (localized to the mitochondria), and MsrB3 (found in the endoplasmic reticulum and mitochondria) [NCBI Gene]. Deficiencies or reduced activity of MsrB have been strongly associated with aging and various pathological conditions, including neurodegenerative diseases like Alzheimer's and Parkinson's, as well as the formation of cataracts and hearing loss [PubMed, PMID: 28600156, PMID: 22532558]. While MsrB represents a significant target for therapeutic strategies aimed at combating oxidative stress-related diseases, there are currently no FDA-approved drugs that specifically modulate its function, although it remains a focus of preclinical research [Antioxidants & Redox Signaling, 2013].

Other names

Selenoprotein RSelRSelenoprotein XSelXMethionine-R-sulfoxide reductase

Stereospecific reduction of methionine-R-sulfoxide residues in proteins to methionine using a thioredoxin-dependent catalytic cycle [PMID: 23024004].