A multi-enzymatic cascade reaction for the stereoselective production of γ-oxyfunctionalyzed amino acids

• Main Authors: Junichi eEnoki, Jaqueline eMeisborn, Ann-Christin eMüller, Robert eKourist
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2016-04-01
• Series: Frontiers in Microbiology
• Subjects: Amino Acids; Dynamic kinetic resolution; Asymmetric oxidation; Enzyme reaction; Isoleucine dioxygenase; Multi-enzyme cascade reaction
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fmicb.2016.00425/full

A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution using an N-acylamino acid racemase and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differ in their optimal temperature and pH-spectra. Their different metal cofactor dependencies lead to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S)-sulfoxide with 97% conversion and 95% de. The combination of these three different biocatalysts allows the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material.