Polycyclic Ketone Monooxygenase (PockeMO): A Robust Biocatalyst for the Synthesis of Optically Active Sulfoxides

Abstract

Abstract:A recently discovered, moderately thermostable Baeyer-Villiger monooxygenase, polycyclic ketone monooxygenase (PockeMO), from Thermothelomyces thermophila has been employed as a biocatalyst in a set of asymmetric sulfoxidations. The enzyme was able to catalyze the oxidation of various alkyl aryl sulfides with good selectivities and moderate to high activities. The biocatalytic performance was able to be further increased by optimizing some reaction parameters, such as the addition of 10% v v −1 of water miscible solvents or toluene, or by performing the conversion at a relatively high temperature (45 • C). PockeMO was found to display an optimum activity at sulfide concentrations of 50 mM, while it can also function at 200 mM. Taken together, the data show that PockeMO can be used as robust biocatalyst for the synthesis of optically active sulfoxides.

Accessing Enantiopure Epoxides and Sulfoxides: Related Flavin‐Dependent Monooxygenases Provide Reversed Enantioselectivity

“…Both enzymes offer a comparatively high activity together with a promising stereoselectivity. 5 was selected as model‐substrate as it contains a relative large substituent on the aromatic ring and was also applied as model‐substrate in various earlier studies . We scaled the reaction to over 10 and 100 mg range.…”

“…Accessing optically pure epoxides and sulfoxides via biocatalytic approaches is a current issue and several mono‐ and dioxygenases, as well as peroxygenases and epoxide hydrolases, have been employed to reach this goal . However, there are still hindrances concerning process stability, due to inactivation or degradation of the enzyme, limited substrate scope and/or insufficient product purity and quality.…”

“…5 was selected as model-substrate as it contains a relative large substituent on the aromatic ring and was also applied as model-substrate in various earlier studies. [65,66] We scaled the reaction to over 10 and 100 mg range. The latter one was only done for DaIndA, as GpStyA was not that easily accessible in high amounts under the tested expression conditions.…”

Investigation of a New Type I Baeyer–Villiger Monooxygenase from Amycolatopsis thermoflava Revealed High Thermodynamic but Limited Kinetic Stability

“…Recombinant expressed cells (1 mL; OD 590 =30) were suspended in PBS (pH 7.4, 50 m m ) to a final concentration of 10 m m substrate (methanol as cosolvent (5 % of total volume)). The components of the reaction (1.02 mL in total) were added to a 25 mL flask, and the reaction was performed at 30 °C by shaking (220 rpm) for 24 h . The product was extracted with ethyl acetate containing 0.1 m m methyl benzoate as the internal standard for GC analysis.…”

“…One of the most stable BVMOs, to date, phenylacetone monooxygenase (PAMO) from thermophilic actinomycete Thermobifida fusca was found by using this method . Recently, genome mining also guided Fraaije and co‐workers to find two other thermostable cyclohexanone monooxygenases ( Tm CHMO and PockeMO), which were isolated from thermophilic bacteria …”