Glucose oxidase was immobilized onto poly(2-hydroxyethyl methacrylate) membranes by covalent bonding through epichlorohydrin. The highest immobilization efficiency was found to be 17.4%. The K(m) values were 5.9 and 8.8 mm for free and bound enzymes, respectively, and the V(max) values were 0.071 and 0.067 mm/min for free and bound enzymes. When the medium was saturated with oxygen K(m) was not altered significantly but V(max) was. The optimum pHs for the free and bound enzyme were determined to be 5 and 6, respectively, and the optimum temperature was 30-degrees-C for both forms. The inactivation constant for the bound enzyme was found to be 1.7 x 10(-4) min-1.