Asymmetric Sulfoxidation of Thioether Catalyzed by Soybean Pod Shell Peroxidase to Form Enantiopure Sulfoxide in Water‐in‐Oil Microemulsions: A Kinetic Model

• Published in: Chemistry, an Asian journal Vol. 16; no. 15; pp. 2075 - 2086
• Main Authors: Li, Huiling, Deng, Yashan, Du, ShanShan, Liu, Cui, Li, Kaiyuan, Xue, Xiao, Xu, Hui, Zhang, Yuanyuan, Yi, Tingting, Gao, Xin
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 02.08.2021
• Subjects: Asymmetric sulfoxidation; Asymmetry; Catalysis; Chemical reactions; Chemistry; Chiral sulfoxides; Electron transfer; Emulsions - chemistry; Glycine max - enzymology; Hydrogen peroxide; Kinetic model; Kinetics; Microemulsions; Models, Biological; Molecular Structure; Natural resources; Oils - chemistry; Oxidation; Peroxidase; Peroxidase - metabolism; Product inhibition; Reaction kinetics; Reaction mechanisms; Soybean pod shell peroxidase; Soybeans; Stereoisomerism; Substrate inhibition; Sulfides - chemistry; Sulfides - metabolism; Sulfoxides; Sulfoxides - chemistry; Sulfoxides - metabolism; Thermal stability; Water - chemistry; Kinetic model; Chiral sulfoxides; Substrate inhibition; Asymmetric sulfoxidation; Soybean pod shell peroxidase
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.202100467

Esomeprazole with chiral sulfoxides structure is used to treat gastric ulcer disease. Soybean pod shell peroxidase (SPSP) is a peroxidase extracted from soybean pods shells which are one of the most abundant natural resources in the world. In the production of chiral sulfoxides catalyzed by SPSP, it is very important to establish the reaction kinetic model and explore the reaction mechanism for the development of the process, however, there is no report on the establishment of the model. Asymmetric sulfoxidation reactions catalyzed by SPSP in water‐in‐oil microemulsions were carried out, and the King‐Altman approach was used to establish a kinetic model. A yield of 91% and e.e. value of 96% for esomeprazole were obtained at the activity of SPSP of 3200 U ml−1 and 50 °C for 5 h. The mechanism with a two‐electron reduction of SPSP‐I is accompanied with a single‐electron transfer to SPSP‐I and nonenzymatic reactions, indicating that three concomitant sub‐mechanisms contribute to the asymmetric oxidation involving five enzymatic and two nonenzymatic reactions, which can represent the asymmetric sulfoxidation of organic sulfides to form enantiopure sulfoxides. With 5.44% of the average relative deviation, a kinetic model fitting experimental data was developed. The enzymatic reactions may follow ping‐pong mechanism with substrate inhibition of H2O2 and product inhibition of esomeprazole, while nonenzymatic reactions follow a power law. Those results indicate that SPSP with a lower cost and higher thermal stability may be used as an effective substitute for horseradish peroxidase. Soybean pod shell peroxidase (SPSP) is a peroxidase extracted from soybean pod shells. Asymmetric sulfoxidation catalyzed by SPSP in water‐in‐oil microemulsions was carried out, in which a yield of 91% and e.e.of 96% for esomeprazole were obtained and a kinetic model fitting experimental data well was developed. The enzymatic reactions may follow a ping‐pong mechanism with substrate inhibition of H2O2 and product inhibition of esomeprazole, while nonenzymatic reactions follow a power law.