ABSTRACTSoluble high molecular weight conjugates of catalase were prepared by intermolecular cross‐linking with glutaraldehyde at pH 7.0. The same reagent was used to prepare high molecular weight soluble conjugates of glucose oxidase with and without catalase activity. For cross‐linking of glucose oxidase the reactions were carried out at pH 4.5 in the presence of bovine serum albumin. No difference in Kmvalues was observed between samples of catalase conjugates and untreated enzyme, either soluble or immobilized. When soluble glucose oxidase‐catalase conjugates were incubated at 55°C for 18 min, only 20% of the original glucose oxidase activity was lost while the untreated enzyme lost 90% of its activity under the same cond