Formal reductive amination has been a main focus of biocatalysis research in recent times. Among theenzymes able to perform this transformation, pyridoxal-5'-phosphate-dependent transaminases haveshown the greatest promise in terms of extensive substrate scope and industrial application. Despiteconcerted research efforts in this area, there exist relatively few options regarding efficient amino donorcosubstrates capable of allowing high conversion and atom efficiency with stable enzyme systems. Herein we describe the implementation of the recently described spuC gene, coding for a putrescinetransaminase, exploiting its unusual amine donor tolerance to allow use of inexpensive and readilyavailable n-butylamine as an alternative to traditional methods. Via the integration of SpuC homologueswith tandem co-product removal and cofactor regeneration enzymes, high conversion could be achievedwith just 1.5 equivalents of the amine with products displaying excellent enantiopurity. Crown Copyright (c) 2017 Published by Elsevier B.V. All rights reserved.