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 li MsrB, 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. A range of sulfoxides including aromatic, heteroaromatic, alkyl and thioalkyl sulfoxides in the S configuration were prepared through kinetic resolution catalyzed by a new MsrB enzyme.