In vitro characterization of an enzymatic redox cascade composed of an alcohol dehydrogenase, an enoate reductases and a Baeyer-Villiger monooxygenase.
Bottom Line: An artificial enzyme cascade composed of an alcohol dehydrogenase, an enoate reductase and a Baeyer-Villiger monooxygenase was investigated in vitro to gain deeper mechanistic insights and understand the assets and drawbacks of this multi-step biocatalysis.Several substrates composed of different structural motifs were examined and provided access to functionalized chiral compounds in high yields (up to >99%) and optical purities (up to >99%).Hence, the applicability of the presented enzymatic cascade was exploited for the synthesis of biorenewable polyesters.
Affiliation: Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, 1060 Vienna, Austria.Show MeSH
Mentions: By performing all enzymatic cascades in a sequential approach and depending on the individual substrate, the formation of several by-products was observed. Conclusively, a direct competition of the alcohol dehydrogenase and the Baeyer–Villiger monooxygenase became evident. A detailed picture of our observations can be seen in Scheme 3. The presence of NADPH promotes the reduction of the saturated ketone to the corresponding alcohol as well the formation to the lactone. Due to the fact, that the ADH reaction is reversible–in contrast to the BVMO oxidation–the overall performance of the cascade is slowed down, but not completely inhibited and the reaction equilibrium is shifted toward the favored product side. Our observations were corroborated by calculation of the relative Gibbs free energy for individual reactions and enzyme activities depicted in Scheme 3 and Table 2. (1a ⇆ 1b and 1c ⇆ 1c-ol).
Affiliation: Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-OC, 1060 Vienna, Austria.