Variant G74C of arylmalonatedecarboxylase (AMDase) from Bordatella bronchoseptica has a unique racemising activity towards profens. By protein engineering, variant G74C/V43A with a 20‐fold shift towards promiscuous racemisation was obtained, based on a reduced activity in the decarboxylation reaction and a two‐fold increase in the racemisation activity. The mutant showed an extended substrate range