A reductive aminase from Aspergillus oryzae
Reductive amination is one of the most important methods for the synthesis of chiral amines. Here we report the
discovery of an NADP(H)-dependent reductive aminase from Aspergillus oryzae (AspRedAm, Uniprot code Q2TW47) that
can catalyse the reductive coupling of a broad set of carbonyl compounds with a variety of primary and secondary amines
with up to >98% conversion and with up to >98% enantiomeric excess. In cases where both carbonyl and amine show
high reactivity, it is possible to employ a 1:1 ratio of the substrates, forming amine products with up to 94% conversion.
Steady-state kinetic studies establish that the enzyme is capable of catalysing imine formation as well as reduction.
Crystal structures of AspRedAm in complex with NADP(H) and also with both NADP(H) and the pharmaceutical
ingredient (R)-rasagiline are reported. We also demonstrate preparative scale reductive aminations with wild-type and
Q240A variant biocatalysts displaying total turnover numbers of up to 32,000 and space-time yields up to 3.73 g l−1 d−1.