• amines;
  • asymmetric synthesis;
  • biocatalysis;
  • imine reductase;
  • Streptomyces
Thumbnail image of graphical abstract

The sharpest enzyme in the box The cover picture shows an Escherichia coli cell containing an over-expressed (S)-imine reductase (IRED) enzyme. In their Communication on p. 3505 ff., F. Leipold et al. describe the development of this engineered whole cell for the asymmetric reduction of a broad range of substituted cyclic 5-, 6-, and 7-membered ring imines to generate the corresponding chiral amines in high yield and enantioselectivity. The whole cell biocatalyst requires only the addition of glucose for cofactor recycling and can be easily generated and used for preparative-scale conversions. Chiral amines are valuable building blocks, for example, as pharmaceutical intermediates, chiral resolving agents, and starting materials for asymmetric syntheses. IRED biocatalysts are thus a valuable addition to the chiral amine biocatalyst toolbox, complementing existing biocatalysts such as transaminases, monoamine oxidases (MAO-N), ammonia lyases, and lipases.