MSRB3 (Methionine Sulfoxide Reductase B3) is a Protein Coding gene. The protein encoded by this gene catalyzes the reduction of methionine sulfoxide to methionine. This enzyme acts as a monomer and requires zinc as a cofactor. This cysteine residue of MSRB3 is conserved in orthologs from yeast to humans and is involved in binding structural zinc. The affected individuals of six unrelated families were homozygous for the same transversion (c.265T>G) in MSRB3. In the inner ear, it is found in the sensory epithelium of the organ of Corti and vestibular end organs as well as in cells of the spiral ganglion. MSRB3-catalyzed reduction of methionine sulfoxides to methionine is essential for hearing. Diseases associated with MSRB3 include Deafness, Autosomal Recessive 74, and Autosomal Recessive Non-Syndromic Sensorineural Deafness Type Dfnb.

> 95 % as determined by SDS-PAGE.