Directed Evolution of the Enzyme Monoamine Oxidase (MAO-N): Highly Efficient Chemo-enzymatic Deracemisation of the Alkaloid (±)-Crispine A.

The article discusses deracemisation process of racemic chiral amines by using variants of the enzyme monoamine oxidase N from Aspergillus niger. It mentions that the deracemisation process involves a combination of an enantioselective enzymatic oxidation of the amine to form imine with a non-selective chemical reduction of the imine or iminium ion back to the racemic starting material. The reaction in this process was monitored by chiral high performance liquid chromatography.