Hydroxynitrile lyase catalyzed cyanohydrin synthesis at high pH-values |
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Authors: | Jan von Langermann Jan-Karl Guterl Martina Pohl Harald Wajant Udo Kragl |
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Institution: | 1.Institut für Chemie,Universit?t Rostock,Rostock,Germany;2.Institut für Molekulare Enzymtechnologie der Heinrich-Heine,Universit?t Düsseldorf,Jülich,Germany;3.Abteilung für Molekulare Innere Medizin, Medizinische Klinik und Poliklinik,Universit?t Würzburg,Würzburg,Germany |
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Abstract: | The application of unusual high pH-values within enzymatic cyanohydrin synthesis has been investigated. Usually enzymatic
cyanohydrin synthesis in two-phase systems requires low pH-values within the aqueous phase to suppress the non-enzymatic side
reaction. In contrast, we investigated the usage of pH-values above pH 6 by using the highly enantioselective (S)-selective hydroxynitrile lyase from Manihot esculenta. With these unusual reaction conditions also the unfavorable substrate 3-phenoxy-benzaldehyde can be converted by the wild
type enzyme with excellent conversion and enantiomeric excess yielding pure (S)-3-phenoxy-benzaldehyde cyanohydrin with an enantiomeric excess of 97%. Although the variant MeHNL–W128A shows a higher activity with respect to this reaction, the enantioselectivity was reduced (85% e.e.(S)). Additionally, a new continuous spectroscopic cyanohydrin assay monitoring the formation of 3-phenoxy-benzaldehyde cyanohydrin
was developed.
Dedicated to Prof. Dr. Christian Wandrey on the occasion of his 65th birthday. |
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Keywords: | Enzyme catalysis Cyanohydrin Hydroxynitrile lyase pH-value |
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