Enzymatic cleavage and formation of cyanohydrins: a reaction of biological and synthetic relevance

Hydroxynitrile lyases (Hnls) catalyse enantioselectively both the cleavage and formation of cyanohydrins. Besides the well known (R)-selective enzyme from almonds, (S)-Hnls have recently become available in larger quantities by cloning and over-expression. The first three-dimensional structure of a Hnl has been established for the enzyme from Hevea brasiliensis. These results are the basis for a still broader application of Hnls for biocatalytic asymmetric syntheses on a preparative scale.