Kinetic Resolution of Aromatic β‐Amino Acids Using a Combination of Phenylalanine Ammonia Lyase and Aminomutase Biocatalysts

Abstract

AbstractAn enzymatic strategy for the preparation of (R)‐β‐arylalanines employing phenylalanine aminomutase and ammonia lyase (PAM and PAL) enzymes has been demonstrated. Candidate PAMs with the desired (S)‐selectivity from Streptomyces maritimus (EncP) and Bacillus sp. (PabH) were identified via sequence analysis using a well‐studied template sequence. The newly discovered PabH could be linked to the first ever proposed biosynthesis of pyloricidin‐like secondary metabolites and was shown to display better β‐lyase activity in many cases. In spite of this, a method combining the higher conversion of EncP with a strict α‐lyase from Anabaena variabilis (AvPAL) was found to be more amenable, allowing kinetic resolution of five racemic substrates and a preparative‐scale reaction with >98% (R) enantiomeric excess. This work represents an improved and enantiocomplementary method to existing biocatalytic strategies, allowing simple product separation and modular telescopic combination with a preceding chemical step using an achiral aldehyde as starting material.magnified image