Kinetic resolution of sulfoxides with high enantioselectivity using a new homologue of methionine sulfoxide reductase B

Optically pure sulfoxides are noteworthy compounds that find wide applications in various industrial fields. Here, we report a methionine sulfoxide reductase B (MsrB) homologue that exhibits high enantioselectivity and broad substrate scope for the kinetic resolution of racemic (rac) sulfoxides. This MsrB homologue, named liMsrB, was identified from Limnohabitans sp. 103DPR2 and showed good activity together with enantioselectivity towards a series of aromatic, heteroaromatic, alkyl and thioalkyl sulfoxides. Chiral sulfoxides in the S configuration were prepared in approximately 50% yield and 92–99% enantiomeric excess through kinetic resolution at an initial substrate concentration of up to 90 mM (11.2 g L−1). This study presents an efficient route for the enzymatic preparation of (S)-sulfoxides through kinetic resolution.