An efficient and selective enzymatic oxidation system for the synthesis of enantiomerically pure D-tert-leucine

D-tert-Leucine was prepared with an enantiomeric excess of >99% by an enzyme-catalyzed oxidative resolution of the racemic mixture of DL-tert-leucine with use of leucine dehydrogenase. The L-amino acid was oxidized completely due to coupling of the primary reaction with a highly efficient irreversible NAD(+)-regenerating step by NADH oxidase.