Novel transaminases for the preparation of pharmaceutically relevant chiral amines Biochemie Proteindesign Transaminasen Biokatalyse Chirale Amine chiral amines biocatalysis protein engineering transaminases Chiral amines represent high value fine chemicals serving as key intermediate products in pharmaceutical chemical and agrochemical industries. In the past decades application of amine transaminases (ATAs) for stereoselective amination of prochiral ketones emerged to an environmentally benign and economically attractive alternative to transition metal catalyzed asymmetric synthesis to afford optically pure amines at industrial scale. However the restricted substrate scope of wild type transaminases prohibited the conversion of particularly sterically demanding substrates making protein engineering indispensable. The following thesis covers elaboration of a novel assay for transaminases (Article I) and identification and development of transaminase variants in order to achieve biocatalytic preparation of a set of pharmaceutically relevant model amines ideally in optically pure form for both stereoisomers preferentially using asymmetric synthesis and most preferably using isopropylamine as cost efficient amine donor co substrate (Article II IV). The aforementioned target amines and the corresponding precursor ketones (see Scheme 4.1) were conceived and provided by the company F. Hoffmann La Roche to attain suitable biocatalysts for a variety of potential intermediates for active pharmaceutical ingredients. Protein engineering of the transaminase scaffolds investigated in this thesis comprised: Initial screening for suitable starting enzyme scaffolds structure guided ...