Mannosyl-oligosaccharide 1,2-alpha-mannosidase

Mannosyl-oligosaccharide 1,2-α-mannosidase (, mannosidase 1A, mannosidase 1B, 1,2-α-mannosidase, exo-α-1,2-mannanase, mannose-9 processing α-mannosidase, glycoprotein processing mannosidase I, mannosidase I, Man9-mannosidase, ManI, 1,2-α-mannosyl-oligosaccharide α- D -mannohydrolase) is an enzyme with systematic name 2-α-mannosyl-oligosaccharide α- D -mannohydrolase. It catalyses the hydrolysis of the terminal (1→2)-linked α- D -mannose residues in the oligo-mannose oligosaccharide Man9(GlcNAc)2.

This enzyme is involved in the synthesis of glycoproteins.

Kifunensine is a potent inhibitor of mannosidase I.