Development of a fast and efficient CE enzyme assay for the characterization and inhibition studies of α‐glucosidase inhibitors

The inhibition of the α‐glucosidase enzyme plays an important role in the treatment of diabetes mellitus. We have established a highly sensitive, fast, and convenient CE method for the characterization of the enzyme and inhibition studies of α‐glucosidase inhibitors. The separation conditions were optimized; the pH value and concentration of the borate‐based separation buffer were optimized in order to achieve baseline separation of p‐nitrophenyl‐α‐d‐glucopyranoside and p‐nitrophenolate. The optimized method using 25 mM tetraborate buffer, pH 9.5, was evaluated in terms of repeatability, LOD, LOQ, and linearity. The LOD and LOQ were 0.32 and 1.32 μM for p‐nitrophenyl‐α‐d‐glucopyranoside and 0.83 and 3.42 μM for p‐nitrophenolate, respectively. The value of the Michaelis–Menten constant (K_m) determined for the enzyme is 0.61 mM, which is in good agreement with the reported data. The RSDs (n = 6) for the migration time was 0.67 and 1.83% for substrate and product, respectively. In the newly established CE method, the separation of the reaction analytes was completed in <4 min. The developed CE method is rapid and simple for measuring enzyme kinetics and for assaying inhibitors.