Purity > 90% as determined by SDS-PAGE. MW: 31.5kDa. Full Length: 1-144aa. N-terminal 6xHis-SUMO-tagged. Arabidopsis thaliana (Mouse-ear cress). Catalyzes the reduction of methionine sulfoxide (MetSO) to methionine in proteins. Plays a protective role against oxidative stress by restoring activity to proteins that have been inactivated by methionine oxidation. MSRB family specifically reduces the MetSO R-enantiomer (By similarity).