title: Propioin synthesis using thiamine diphosphate-dependent enzymes.
abstract: Benzaldehyde lyase (BAL, EC 4.1.2.38) from Pseudomonas fluorescens and benzoylformate decarboxylase (BFD, EC 4.1.1.7) from Pseudomonas putida are thiamine diphosphate-dependent enzymes. These enzymes share a common tetrameric structure and catalyze various C--C-bond forming and breaking reactions. Here we describe a detailed study of the asymmetric synthesis of propioin from propanal catalyzed by BAL or BFD in aqueous solution in a batch reactor. Both enzymes are deactivated in the presence of high concentration of propanal. Compared to BAL, BFD is more stable under reaction conditions as well as during storage. The kinetic studies showed a typical Michaelis-Menten kinetic for BAL with a maximal specific reaction rate of 26.2 U/mg and an unusually high K(M) of 415 mM, whereas the v/[S]-plot for BFD is almost linear in the concentration range (100-1500 mM) investigated. Both enzymes produce propioin with opposite enantiomeric excess: BAL produced the (S)-propioin (ee of 35%), whereas BFD yielded the (R)-enantiomer (ee of 67%).
authors.affiliation: Biochemical Engineering, RWTH Aachen University, Worringer Weg 1, Aachen 52056, Germany. mikolajek@biovt.rwth-aachen.de
authors.forename: Renaud J
authors.initials: RJ
authors.lastname: Mikolajek
authors.forename: Antje C
authors.initials: AC
authors.lastname: Spiess
authors.forename: Martina
authors.initials: M
authors.lastname: Pohl
authors.forename: Jochen
authors.initials: J
authors.lastname: Büchs
mesh_terms: D000446:Aldehyde-Lyases / Q000378:metabolism*; D019149:Bioreactors; D002262:Carboxy-Lyases / Q000378:metabolism*; D006588:Hexanones / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000201:enzymology; D016958:Pseudomonas putida / Q000201:enzymology; D013835:Thiamine Pyrophosphate / Q000378:metabolism*
chemical_list: D006588:Hexanones; C523189:propioin; D002262:Carboxy-Lyases; C019778:benzoylformate decarboxylase; D000446:Aldehyde-Lyases; C059416:benzaldehyde lyase; D013835:Thiamine Pyrophosphate