A system for ω-transaminase mediated (R)-amination using l-alanine as an amine donor†
Chiral amines are important building blocks for fine chemicals and pharmaceuticals. Consequently, various biocatalytic routes in particular using ω-transaminases (ω-TAs) have been developed recently. Although catalysts for the synthesis of both enantiomers are available, the application of alanine dependent (R)-selective ω-TAs is less favourable due to the requirement of the more expensive D-alanine as an amine donor. Here we describe an efficient method for (R)-amination using ω-TAs in combination with an alanine racemase (AlaR). In this case, the readily available L-alanine can be used as an amine donor leading to improved atom efficiency and significantly reduced costs.