Purity: > 90% by SDS - PAGE Format: Liquid. In 20mM Tris-HCl buffer (pH 8.0) containing 1mM DTT, 10% glycerol, 0.1M NaCl. Peptide methionine sulfoxide reductase A, also known msrA, is an enzyme that catalyzes the reversible oxidation-reduction of methionine sulfoxide in proteins to methionine. This protein could have an important function as a repair enzyme for proteins that have been inactivated by oxidation. Recombinant E.coli msrA protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.