Bridging the bridge —Stabilization of CalB against H2O2 and its application in epoxidation reactions

Publication date: Available online 5 January 2017 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Max Steinhagen, Anna Gräbner, Janine Meyer, Angelika E.W. Horst, Anja Drews, Dirk Holtmann, Marion B. Ansorge-Schumacher Chemo-enzymatic reactions combine the advantages of chemistry and biocatalysis. Chemical synthesis provides precursor molecules and low costs, whereas the application of enzymes provides selectivity. Additionally, the mild reaction conditions of enzymatic approaches allow the chemical application of intermediates and/or products that otherwise are not accessible. One example is the in situ production of peroxycarboxylic acids (peracids) by Candida antarctica lipase B (CalB). In contrast to the harsh conditions of chemical peracid synthesis, CalB catalyzed reactions run at low temperatures and without additives. Unfortunately, the enzyme is rapidly inactivated by the oxidative environment. Herein, we report on CalB stabilization by preventing disulfide cleavage after H2O2 exposure. Therefore, a bismaleimide functionalized linker was used to convert all the enzyme’s disulfide bridges to more stable thioether linkages. These bonds are still affected by hydrogen peroxide but will not open upon oxidation. A two- to fourfold excess of this linker was optimal to avoid enzyme oligomerization. At the same time, a 1.5 fold increase in half life time after exposure to hydrogen peroxide was achieved. To our knowledge, such an approach to intramole...
Source: Journal of Molecular Catalysis B: Enzymatic - Category: Biochemistry Source Type: research