Interaction of concanavalin A with native and denatured forms of jackbean alpha-D-mannosidase.

Tetrameric alpha-D-mannosidase from jackbean is a glycoprotein containing at least one mannosylated oligosaccharide. In the native enzyme, the oligosaccharide is sterically masked from interaction with either endoglucosaminidase H or concanavalin A. Denaturation into subunits permits endoglucosaminidase hydrolysis and removal of the oligosaccharide. The mannosyl residues are attached only to the heavy type of subunit. Removal of the oligosaccharide(s) from the denatured heavy subunit requires the joint action of both alpha-D-mannosidase and N-acetyl-beta-D-glucosaminidase.