Dopamine-polyethyleneimine co-deposition cellulose filter paper for α-Glucosidase immobilization and enzyme inhibitor screening

In this work, cellulose filter paper (CFP), which is inexpensive and commercially available, was used as the carrier, and the immobilized alpha-glucosidase was obtained by two steps: firstly, the surface of CFP was modified by polydopamine/polyethyleneimine (PDA/PEI) co-deposition method to obtain CFP-PDA/PEI with a uniform coating of rich positive charge; subsequently, alpha-glucosidase was immobilized on the CFP-PDA/PEI by electrostatic adsorption. The free enzyme and immobilized enzyme have the same optimal temperature (70 degrees C) and pH (8.0), and their K-m is similar, which is 2.2 and 2.8, respectively. These results show that the immobilization process does not change the properties of the enzyme greatly. The immobilized enzyme still maintains 75.6% of its initial activity after 10 repeated uses, showing good reusability. The excellent repeatability (RSD = 2.2%, n = 5) and the verification of competitive inhibitor (acarbose) illustrates the reliability of the immobilized enzymes for enzyme inhibitor screening. Finally, combined with CE, a screening method based immobilized alpha-glucosidase was proposed and applied to screen the alpha-glucosidase inhibitory from 10 kinds of Traditional Chinese medicines (TCMs) in vitro. The results indicated that the method was a very effective tool for screening potential alpha-glucosidase inhibitors from TCMs.

Automated summary

In this study, cellulose filter paper was used as a carrier for immobilized alpha-glucosidase, showing that the immobilized enzyme maintains good activity and stability even after repeated use. The method proved to be effective for screening potential alpha-glucosidase inhibitors from Traditional Chinese medicines.