MSRBHis protein.MSRB is His-tagged at the N-terminal.Like most bacteria, Escherichia coli expresses a singleMSRB (Methionine-R-sulfoxide reductase, EC1.8.4.6;accession number NP416292) that carries out the reduction of methionine-R-sulfoxide to methionine. The E. colienzyme - like the two human enzymes offered by JenaBioscience-belong to a group of MsrBs, that possess ametal binding site composed of two CXXC motifs. Thebound metal (zinc or iron) may stabilize the conformationof the enzymes. Purity >90% by SDS-PAGE