title: Influence of reaction conditions on the enantioselectivity of biocatalyzed C-C bond formations under high pressure conditions.
abstract: Benzoylformate decarboxylase (BFD, EC 4.1.1.7) is a homotetrameric thiamine diphosphate (ThDP)-dependent enzyme which catalyzes the synthesis of chiral 2-hydroxyketones accepting a broad range of aldehydes as substrates. In this study the synthesis of 2-hydroxypropiophenone (2-HPP) from benzaldehyde and acetaldehyde was catalyzed by three BFD variants namely BFD F464I, BFD A460I and BFD A460I-F464I. This paper reports the effect of hydrostatic pressure up to 290 MPa when the reactions were carried out at different benzaldehyde concentrations (5-40 mM) as well as at different pH values (7.0-8.5). Acetaldehyde concentration was fixed at 400 mM in all biotransformations. Reactions performed at high benzaldehyde concentrations and at high hydrostatic pressures showed an increase in (R)-2-HPP formation catalyzed by all BFD variants. For BFD A460I-F464I we observed an increase in the ee of (R)-2-HPP up to 80%, whereas at atmospheric conditions this variant synthesizes (R)-2-HPP with an ee of only 50%. Alkaline conditions (up to pH 8.5) and high hydrostatic pressures resulted in an increase of (R)-2-HPP synthesis, especially in the case of BFD A460I and BFD F464I.
authors.affiliation: Institute of Technical Biocatalysis, Hamburg University of Technology(TUHH), Denickestrasse 15, D-21073 Hamburg, Germany.
authors.forename: Selin
authors.initials: S
authors.lastname: Kara
authors.forename: Wei Sing
authors.initials: WS
authors.lastname: Long
authors.forename: Marco
authors.initials: M
authors.lastname: Berheide
authors.forename: Stephanie
authors.initials: S
authors.lastname: Peper
authors.forename: Bernd
authors.initials: B
authors.lastname: Niemeyer
authors.forename: Andreas
authors.initials: A
authors.lastname: Liese
mesh_terms: D001547:Benzaldehydes / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D055162:Biocatalysis / Q000187:drug effects; D002262:Carboxy-Lyases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006910:Hydroxypropiophenone / Q000737:chemistry / Q000378:metabolism; D011312:Pressure; D013237:Stereoisomerism; D013379:Substrate Specificity / Q000187:drug effects
chemical_list: D001547:Benzaldehydes; D006910:Hydroxypropiophenone; D002262:Carboxy-Lyases; C019778:benzoylformate decarboxylase; C032175:benzaldehyde