Preparation of polymeric urease discs by an electron beam irradiation technique.

A preparation method of immobilized urease discs by an electron beam irradiation technique was developed, and the relationship between enzyme activity and preparation conditions was investigated. The immobilized urease disc was a thin circular film (200 microm, 5 mm phi) that is useful for biomedical applications. The activity of urease irradiated with 1 Mrad at room temperature was protected by the presence of cysteine. The activity of the immobilized urease discs was studied as a function of monomer concentration (80-90%) and the thicker disc gave a high activity. The durability of the immobilized urease discs gave a high activity. The durability of the immobilized urease discs was evaluated by repeated batch enzyme reactions, and a high activity yield (80-85%) was obtained.