glucose oxidase and catalase were immobilized by attaching them to nylon fibers that had been treated with triethyloxonium-tetrafluoroborate, diaminohexane and glutardialdehyde according to morris, campbell and hornby (1975) this method assures that the enzymes are bound to a side chain of the polyamide structure. enzyme activity (as measured by the o/sub 2/-uptake and by microcalorimetry) was found to be unchanged after 2 years. the apparent k/sub m/-constants of the immobilized enzymes with glucose were the same as those for enzymes in solution. god and catalase immobilized in poly(acrylamide) gel had the same k/sub m/-value. despite the high stability during storage, the radiation induced inactivation of enzymes immobilized on gel or chromosorb, an inorganic carrier, was of the same order of magnitude as that of the dissolved enzymes. the enzymes bound to nylon fibers showed a higher radiation sensitivity. this might have been caused by an additional attack on the binding site of the carrier