Tailoring d-Amino Acid Oxidase from the Pig Kidney to R-Stereoselective Amine Oxidase and its Use in the Deracemization of aMethylbenzylamine**

The deracemization of racemic amines to yield enantioenriched amines using S-stereoselective amine oxidases (AOx) has recently been attracting attention. However, R-stereoselective AOx that are suitable for deracemization have not yet been identified. An R-stereoselective AOx was now evolved from porcine kidney D-amino acid oxidase (pkDAO) and subsequently use for the deracemization of racemic amines. The engineered pkDAO, which was obtained by directed evolution, displayed a markedly changed substrate specificity towards Ramines. The mutant enzyme exhibited a high preference towards the substrate -methylbenzylamine and was used to synthesize the Samine through deracemization. The findings of this study indicate that further investigations on the structure-activity relationship of AOx are warranted and also provide a new method for biotransformations in organic synthesis.