InspIRED by Nature: NADPH-Dependent Imine Reductases (IREDs) as Catalysts for the Preparation of Chiral Amines

Imine reductases (IREDs) are NADPH-dependent oxidoreductases that catalyse the asymmetric reduction of cyclic prochiral imines to amines, with excellent stereoselectivity. Since their discovery, stereocomplementary IREDs have been applied to the production of both (S) and (R) cyclic secondary amines, and the expansion in gene sequences recently identified has hinted at new substrate ranges that extend into acyclic imines and even suggest the possibility of asymmetric reductive amination from suitable ketone and amine precursors. Structural studies of various IREDs are beginning to reveal the complexities inherent in determining substrate range, stereoselectivity and mechanism in these enzymes, which represent a valuable emerging addition to the toolbox of available biocatalysts for chiral amine production. Imine reductases (IREDs) are NADPH-dependent oxidoreductases that catalyse the asymmetric reduction of cyclic prochiral imines to amines, with excellent stereoselectivity. The recent identification of the first IREDs has led to a rapid growth in research in this area and many studies on the application, structure and mechanism of the enzymes reveal IREDs to be a valuable addition to the toolbox of biocatalysts for chiral amine production.