α-D-Mannosidase of kiwifruit was purified from flesh by ammonium sulfate fractionation and column chromatography on DEAE-cellulose, hydroxylapatite, Sepharose CL-6B and Con A-Sepharose 4B. The purified enzyme was almost homogeneous on disc gel electr phoresis. Its molecular weight was estimated to be 86000 by gel filtration and 83000-85000 by SDS-polyacrylamide gel electrophoresis. The pH optimum was found to be 5.0-5.5, The enzyme was stable in the pH range of 6.5-7.5, and up to 55°C during 10 min incubation. It showed Km value of 6.7mM for p-nitrophenyl α-D-mannoside. Its activity was stimulated by Zn2+. It catalyzed the hydrolysis of ovalbumin glycopeptide and yeast mannan.
