Asymmetric reduction of racemic sulfoxides by dimethyl sulfoxide reductases from Rhodobacter capsulatus, Escherichia coli and Proteus species.

The enantioselective reduction of racemic sulfoxides by dimethyl sulfoxide reductases from Rhodobacter capsulatus, Escherichia coli, Proteus mirabilis and Proteus vulgaris was investigated. Purified dimethyl sulfoxide reductase from Rhodobacter capsulatus catalysed the selective removal of (S)-methyl p-tolyl sulfoxide from a racemic mixture of methyl p-tolyl sulfoxide and resulted in an 88% recovery of enantiomerically pure (R)-methyl p-tolyl sulfoxide. Rhodobacter capsulatus was shown to be able to grow photoheterotrophically in the presence of certain chiral sulfoxides under conditions where a sulfoxide is needed as an electron sink.