Most of bioactive species such as enzyme and antibody will be damaged and lose part of their bioactivity when they are irradiated by ionizing radiation at room temperature. Low temperature could somewhat control the effect

so kaetsu and his co-workers developed an entrapping technique at low temperature ( - 78℃). On the other hand

some enzymes such as catalase and house radish peroxidase have so-called radiation-induced post-deactivation effect as well. In order to avoid the trouble in performance and loss of bioactivity

a physical ent-rapping of bioactive species via preirradiation polymerization at room temperature were deve-loped in the Authors'lab. In this work we developed this technique. The glucose oxidase was entrapped in polyacrylamide hydrogel ind uced by pre-irradiation. Experiments under several different conditions such as absorbed dose and concentrations of enzymes

monomer and crosslinking agent were carried out. The results showed that this technique can be used ex-tensively in various enzyme.