Cleaves the distal alpha 1,2-linked glucose residue from the Glc(3)Man(9)GlcNAc(2) oligosaccharide precursor highly specifically (PubMed:9363442). Seems to play a role in beta-1,6-glucan synthesis (PubMed:8576053). H2O + N(4)-(alpha-D-Glc-(1->2)-alpha-D-Glc-(1->3)-alpha-D-Glc-(1->3)-alpha-D-Man-(1->2)-alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-[alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-[alpha-D-Man-(1->2)-alpha-D-Man-(1->6)]-alpha-D-Man-(1->6)]-beta-D-Man-(1->4)-beta-D-GlcNAc-(1->4)-alpha-D-GlcNAc)-L-asparaginyl-[protein] = beta-D-glucose + N(4)-(alpha-D-Glc-(1->3)-alpha-D-Glc-(1->3)-alpha-D-Man-(1->2)-alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-[alpha-D-Man-(1->2)-alpha-D-Man-(1->3)-[alpha-D-Man-(1->2)-alpha-D-Man-(1->6)]-alpha-D-Man-(1->6)]-beta-D-Man-(1->4)-beta-D-GlcNAc-(1->4)-alpha-D-GlcNAc)-L-asparaginyl-[protein] Miglitol is an effective inhibitor at 1 mM. Glycan metabolism; N-glycan degradation. N-glycosylated. Displays phenotypes characteristic of cell wall defects such as hypersensitivity to calcofluor white and resistance to K1 killer toxin, and results in a 50% reduction of cell wall beta-1,6-glucan level (PubMed:9363442). Abolishes glucosidase I activity (PubMed:9363442). Present with 2840 molecules/cell in log phase SD medium. Belongs to the glycosyl hydrolase 63 family.