Engineering the Active Site of the Amine Transaminase from Vibrio fluvialis for the Asymmetric Synthesis of Aryl-Alkyl Amines and Amino Alcohols

Although the amine transaminase from Vibrio fluvialis has often been applied as a catalyst for the biocatalytic preparation of various chiral primary amines, it is not suitable for the transamination of a-hydroxy ketones and aryl-alkyl ketones bearing an alkyl substituent larger than a methyl group. We addressed this problem through a systematic mutagenesis study of active site residues to expand its substrate scope towards two bulky ketones. We identified two mutants (F85L/V153A and Y150F/V153A) showing 30-fold increased activity in the conversion of (S)-phenylbutylamine and (R)-phenylglycinol, respectively. Notably, they facilitated asymmetric synthesis of these amines with excellent enantiomeric purities of 98% ee.