Enhanced Activity of Immobilized Pepsin Nanoparticles Coated on Solid Substrates Compared to Free Pepsin

Pepsin, an aspartic peptidase, is used for a variety of applications in industry. Immobilization of pepsin onto solid supports can offer advantages such as easier separation of the enzyme from the product and the possibility of repetitive use of a single batch of enzyme.

In the present work, nanoparticles of pepsin were generated in an aqueous solution using high intensity ultrasound, and were subsequently immobilized on low-density polyethylene (PE) films, or on polycarbonate (PC) plates, or on microscope glass slides. The leaching properties, kinetic parameters, and the catalytic activity of the immobilized enzyme on the three surfaces were compared. Catalytic activities of pepsin deposited onto the three surfaces as well as free pepsin, without sonication, and free pepsin NPs were compared at various pH levels and temperatures. Compared to native pepsin, pepsin coated onto PE showed the best catalytic activity in all the examined parameters. A remarkable observation is that immobilized pepsin on all the surfaces was still active to some extent at pH 7, while free pepsin was completely inactive.