37143-54-7Relevant articles and documents
Parallel interconnected kinetic asymmetric transformation (PIKAT) with an immobilized ω-transaminase in neat organic solvent
B?hmer, Wesley,Koenekoop, Lucien,Mutti, Francesco G.,Simon, Timothée
, (2020/05/25)
Comprising approximately 40% of the commercially available optically active drugs, α-chiral amines are pivotal for pharmaceutical manufacture. In this context, the enzymatic asymmetric amination of ketones represents a more sustainable alternative than traditional chemical procedures for chiral amine synthesis. Notable advantages are higher atom-economy and selectivity, shorter synthesis routes, milder reaction conditions and the elimination of toxic catalysts. A parallel interconnected kinetic asymmetric transformation (PIKAT) is a cascade in which one or two enzymes use the same cofactor to convert two reagents into more useful products. Herein, we describe a PIKAT catalyzed by an immobilized ω-transaminase (ωTA) in neat toluene, which concurrently combines an asymmetric transamination of a ketone with an anti-parallel kinetic resolution of an amine racemate. The applicability of the PIKAT was tested on a set of prochiral ketones and racemic α-chiral amines in a 1:2 molar ratio, which yielded elevated conversions (up to >99%) and enantiomeric excess (ee, up to >99%) for the desired products. The progress of the conversion and ee was also monitored in a selected case. This is the first report of a PIKAT using an immobilized ωTA in a non-aqueous environment.
Stabilization of an amine transaminase for biocatalysis
Chen, Shan,Land, Henrik,Berglund, Per,Humble, Maria Svedendahl
, p. 20 - 28 (2015/12/17)
The amine transaminase from Chromobacterium violaceum (Cv-ATA) is a well-known enzyme to achieve chiral amines of high enantiomeric excess in laboratory scales. However, the low operational stability of Cv-ATA limits the enzyme applicability on larger scales. In order to improve the operational stability of Cv-ATA, and thereby extending its applicability, factors (additives, co-solvents, organic solvents and different temperatures) targeting enzyme stability and activity were explored in order to find out how to store and apply the enzyme. The present investigation shows that the melting point of Cv-ATA is improved by adding sucrose or glycerol, separately. Further, by storing the enzyme at higher concentrations and in co-solvents, such as; 50% glycerol, 20% methanol or 10% DMSO, the active dimeric structure of Cv-ATA is retained. Enzyme stored in 50% glycerol at -20 °C was e.g., still fully active after 6 months. Finally, the enzyme performance was improved 5-fold by a co-lyophilization with surfactants prior to usage in isooctane.
Enzymatic racemization of amines catalyzed by enantiocomplementary ω-Transaminases
Koszelewski, Dominik,Grischek, Barbara,Glueck, Silvia M.,Kroutil, Wolfgang,Faber, Kurt
experimental part, p. 378 - 383 (2011/03/21)
A strategy for the biocatalytic racemization of primary α-chiral amines was developed by employing a pair of stereocomplementary PLP-dependent ω-transaminases. The interconversion of amine enantiomers proceeded through reversible transamination by a prochiral ketone intermediate, either catalyzed by a pair of stereocomplementary ω-transaminases or by a single enzyme possessing low stereoselectivity. To tune the system, the type and concentration of a nonchiral amino acceptor proved to be crucial. Finally, racemization could be achieved by the cross-transamination of two different amines without a requirement for an external amino acceptor. Several synthetically and industrially important amines could be enzymatically racemized under mild reaction conditions. ω-Transaminases play ping-pong: A biocatalytic protocol for the 'clean' racemization of α-chiral prim-amines was developed by an equilibrium-controlled deamination/amination sequence catalyzed by a pair of (R)- and (S)-ω-transaminases (see scheme).
