초록
<P>Optically pure beta-amino acids are of high pharmacological significance since they are used as key ingredients in many physiologically active compounds. Despite a number of enzymatic routes to these compounds, an efficient synthesis of beta-amino acids continues to pose a major challenge for researchers. omega-Transaminase has emerged as an important class of enzymes for generating amine compounds. However, only a few omega-transaminases have been reported so far which show activity towards aromatic beta-amino acids. In this study, (S)-omega-transaminase from Burkholderia graminis C4D1M has been functionally characterized and used for the production of chiral aromatic beta-amino acids via kinetic resolution. The enzyme showed a specific activity of 3.1 U/mg towards rac-beta-phenylalanine at 37 degrees C. The K-m and K-cat values of this enzyme towards rac-beta-phenylalanine with pyruvate as the amino acceptor were 2.88 mM and 91.57 min(-1) respectively. Using this enzyme, racemic beta-amino acids were kinetically resolved to produce (R)-beta-amino acids with an excellent enantiomeric excess (> 99%) and similar to 50% conversion. Additionally, kinetic resolution of aromatic beta-amino acids was performed using benzaldehyde as a cheapamino acceptor. (C)2015 Elsevier B.V. All rights reserved.</P>