Improvement of a Stereoselective Biocatalytic Synthesis by Substrate and Enzyme Engineering: 2-Hydroxy-(4′-oxocyclohexyl)acetonitrile as the Model

Authors

  • Manuela Avi Dr.,

    1. Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 16, 8010 Graz (Austria)
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    • These authors contributed equally to the work.

  • Romana M. Wiedner Dr.,

    1. Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz (Austria), Fax: (+43) 316-873-4071
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    • These authors contributed equally to the work.

  • Herfried Griengl Prof.,

    1. Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 16, 8010 Graz (Austria)
    2. Research Centre Applied Biocatalysis, Petersgasse 14, 8010 Graz (Austria)
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  • Helmut Schwab Prof.

    1. Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz (Austria), Fax: (+43) 316-873-4071
    2. Research Centre Applied Biocatalysis, Petersgasse 14, 8010 Graz (Austria)
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Abstract

Even if biocatalysis is finding increasing application, it still has to gain widespread use in synthetic chemistry. Reasons for this are limitations that enzymes have with regard to substrate range, reaction scope, and insufficient selectivity with unnatural compounds. These shortcomings can be challenged by enzyme and/or substrate engineering, which are employed to alter substrate specificity and enhance the enzyme selectivity toward unnatural substrates. Herein, these two approaches are coupled to improve the hydroxynitrile lyase catalyzed synthesis of 2-hydroxy-(4′-oxocyclohexyl)acetonitrile (4). The ketone functionality is masked as an enol ether, and the oxynitrilase of Hevea brasiliensis is engineered towards this masked substrate to give the product with a high optical purity and to drastically lower the amount of enzyme needed.

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