An Aminocaprolactam Racemase from Ochrobactrum anthropi with Promiscuous Amino Acid Ester Racemase Activity.

The kinetic resolution of amino acid esters (AAEs) is a useful synthetic strategy for the preparation of single-enantiomer amino acids. The development of an enzymatic dynamic kinetic resolution (DKR) process for AAEs, which would give a theoretical yield of 100 % of the enantiopure product, would require an amino acid ester racemase (AAER); however, no such enzyme has been described. We have identified low AAER activity of 15 U mg in a homologue of a PLP-dependent α-amino ϵ-caprolactam racemase (ACLR) from Ochrobactrum anthropi.