No abstract

An MsrA homologue with extremely high substrate tolerance and a wide substrate scope for the biocatalytic preparation of enantiopure sulfoxides.

Here we report an environmentally friendly method for the preparation of chiral sulfoxides under high substrate concentration using recombinant methionine sulfoxide reductase A from Pseudomonas monteilii (pmMsrA) as a biocatalyst. Our results show that this enzyme can effectively accomplish the preparation of (R)‐sulfoxides with approximately 50 % yield and 94–99 % enantiomeric excess through asymmetric reductive resolution of racemic sulfoxide. With the establishment of the enzyme regeneration system, the initial substrate concentration could be increased 40–100 times compared to our original report. The (R)‐sulfoxides were obtained with high enantioselectivity under the substrate concentration up to 200 mm (approximately 32 g L−1), representing a quite high substrate concentration in biocatalytic preparation of chiral sulfoxides. Moreover, this system showed fairly good activity and enantioselectivity towards a series of ortho‐ and para‐substituted phenyl methyl sulfoxides under high substrate concentration.