Lactam–amide graft copolymers as novel support for enzyme immobilization

Abstract

A graft random copolymer of N-vinyl-2-pyrrolidone and N,NЈ-dimethylacrylamide onto polypropylene was synthesized using a simultaneous gamma radiation technique from a 60 Co source, so that the hydrogel poly(propylene-g-vinylpyrrolidone-, thus produced by grafting, could be used as a support for enzyme immobilization. The grafted spheres showed very good swelling behavior in water due to the incorporation of hydrophilicity in the PP spheres. The influence of pH and temperature on as well as the determination of the kinetic parameters, K M and V max , for both immobilized and soluble invertase were determined. PP-g-(VP-co-DMAM) grafting onto the PP spheres caused a significant change in the water content of the support and was more pronounced for the spheres with a high degree of grafting. A porous structure of the polymeric spheres was observed by scanning electron microscopy (SEM). The porous structure contributed to the reaction rate decrease due to diffusional effects, as shown by the larger K M value observed for immobilized invertase relative to the free enzyme. The enzyme affinity for the substrate (K M /V max ) remains quite good after immobilization. The thermal stability of immobilized invertase was significatively higher than that of the free enzyme and a displacement of 20°C was observed for the immobilized enzyme.

Invertase immobilised on montmorillonite: reusability enhancement and reduction in leaching

“…It is therefore clear that diffusional restrictions to mass transfer operate strongly for immobilised invertase. Due to these limitations, the sucrose molecules cannot effectively access the active sites of invertase and hence formation of enzymesubstrate complex becomes more difficult leading to a decreased affinity for substrate and consequently a high K m value [20]. Other authors have also obtained similar results [21,22].…”

Enhanced pH and thermal stabilities of invertase immobilized on montmorillonite K-10

“…For this reason, the topic of bioactive molecules immobilized on a great variety of supports with various organic and inorganic chemical compositions and shapes is of increasing current interest (De Queiroz, Vargas, Higa, Ribeiro, & Vitolo, 2002). Invertase or b-fructofuranosidase (EC 3.2.1.26) catalyzes the hydrolysis of sucrose to glucose and fructose.…”

Ion-Imprinted Polymer-Based Receptors for Sensitive and Selective Detection of Mercury Ions in Aqueous Environment

“…This increase in conductivity of graphene sheets is due to its high surface area in comparison to all other polymer thin films, and secondly, it contributes to sensitivity because of its oxygen and mercuric ion interaction. N-vinylpyrrolidone (NVP) shows good biocompatibility due to their hydrophilic nature and low cytotoxicity [30][31][32][33][34][35][36][37]. Electron-deficient Hg 2+ ions interact with electron-rich moieties of NVP/ EGDMA.…”