AbstractHigh activity alkaline protease was obtained when the enzyme was immobilized on Dowex MWA‐1 (mesh 20–50) with 10% glutaraldehyde in chilled phosphate buffer (M/15, pH 6.5). Activity yields of the protease and rennet were 27 and 29, respectively. The highest activities appeared at 60°C, pH 10 for alkaline protease and 50°C, pH 4.0 for rennet. The properties of both proteases were not essentially changed by the immobilization except that theKmvalues of both enzymes were increased about tenfold as a result of immobilization. Both proteases in the immobilized state were more stable than those in the free state at 60°C. Other peptide hydrolases, β‐galactosidase, invertase, and glucoamylase, were successfully immobilized with high activities, but lipase, hexokinase, glucose‐6‐phosphate dehydrogenase, and xanthine oxidase be