Further Purification and Characterization of α-Mannosidase from Hog Kidney*

α-Mannosidase EC 3.2.1. 24 was purified 2, 100-fold over the crude extract from hog kidney. The final preparation was essentially homogeneous on disc electrophoresis. Molecular weight of the enzyme was about 42, 000 on disc electrophoresis in the presence of sodium dodecyl sulphate. The enzyme was a glycoprotein containing 8.0% of mannose and 3.3% of glucosamine. The enzyme showed a broad aglycon specificity, and was capable of hydrolyzing α-(1→2), α-(1→3), and α-(1→6) linkages of oligomannosides, α-Man-(1→3)-G1cNAc, α-Man-(1→6)-G1cNAc, and the α-linkage of α-Man-(1→4)-B-Man-(1→4)-Man. Michaelis constants and maximum velocities with oligomannosides varied from one substrate to another.