Cover Picture: Phenylalanine Ammonia-Lyase-Catalyzed Deamination of an Acyclic Amino Acid: Enzyme Mechanistic Studies Aided by a Novel Microreactor Filled with Magnetic Nanoparticles (ChemBioChem 16/2015)

The cover picture shows phenylalanine ammonia‐lyase (PAL) immobilized on magnetic nanoparticles (MNPs) and its use in a magnetic microfluidic reactor with in‐line UV detection to confirm for the first time that propargylglycine could be reversibly and stereospecifically transformed by PAL. The authors describe how a non‐aromatic, acyclic amino acid was transformed to (E)‐pent‐2‐ene‐4‐ynoate. Experiments and QM/MM calculations showed that this was only possible through a covalent intermediate with a bond between the amino group of the substrate and the MIO prosthetic group. Their findings open up new opportunities for the application of the MIO enzyme toolbox towards non‐aromatic acyclic substrates. More details can be found in the Communication by C. Paizs, L. Poppe et al. on page 2283 in Issue 16, 2015 (DOI: 10.1002/cbic.201500444).