An online immobilized pepsin microreactor based on polymer monoliths for screening inhibitors from natural products

As pepsin is one of the most important enzymes in the digestive system and is closely related to several diseases, an online system was developed to study the kinetics of pepsin and screen inhibitors from natural products. In the present study, pepsin was immobilized onto an organic polymer monolith with glutaraldehyde as the linker. Both the immobilization and electrophoresis conditions were optimized to improve the performance of the immobilized enzyme reactor (IMER). The as-prepared IMER showed good reusability as it retained 95.9% of the relative activity after 40 repeated runs. As for the storage stability, it only lost 15.1% of its initial activity after 36 days of storage at 4 degrees C without other use. Moreover, the Michaelis-Menten constant (K-m) of the immobilized pepsin was determined to be 0.51 mmol L-1. Eventually, the developed system was applied to screen pepsin inhibitors from 9 natural products.