title: Methionine sulfoxide reductase A is a stereospecific methionine oxidase.
abstract: Methionine sulfoxide reductase A (MsrA) catalyzes the reduction of methionine sulfoxide to methionine and is specific for the S epimer of methionine sulfoxide. The enzyme participates in defense against oxidative stresses by reducing methionine sulfoxide residues in proteins back to methionine. Because oxidation of methionine residues is reversible, this covalent modification could also function as a mechanism for cellular regulation, provided there exists a stereospecific methionine oxidase. We show that MsrA itself is a stereospecific methionine oxidase, producing S-methionine sulfoxide as its product. MsrA catalyzes its own autooxidation as well as oxidation of free methionine and methionine residues in peptides and proteins. When functioning as a reductase, MsrA fully reverses the oxidations which it catalyzes.
authors.affiliation: Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, MD 20892-8012, USA.
authors.forename: Jung Chae
authors.initials: JC
authors.lastname: Lim
authors.forename: Zheng
authors.initials: Z
authors.lastname: You
authors.forename: Geumsoo
authors.initials: G
authors.lastname: Kim
authors.forename: Rodney L
authors.initials: RL
authors.lastname: Levine
mesh_terms: D055162:Biocatalysis; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D051150:Methionine Sulfoxide Reductases / Q000378:metabolism*; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D051150:Methionine Sulfoxide Reductases