Catalytic subunit of glucosidase 2, which cleaves sequentially the 2 innermost alpha-1,3-linked glucose residues from the Glc(2)Man(9)GlcNAc(2) oligosaccharide precursor of immature glycoproteins. H2O + N(4)-(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-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] (N-glucan mannose isomer 9A1,2,3B1,2,3) H2O + 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] = beta-D-glucose + N(4)-(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] Glycan metabolism; N-glycan metabolism. Heterodimer of a catalytic subunit alpha (gls2) and a subunit beta (gtb1). Gls2 and alg6 double mutant cells that transfer Man(9)GlcNAc(2) and that are unable to remove the glucose units as they lack gls2, grow at 37 degrees Celsius, but are characterized by swollen cells, displaying pear, lemon and round shapes and have, when grown at 28 degrees Celsius, a phenotype of growth and morphology almost identical to that of wild-type cells, indicating that facilitation of glycoprotein folding mediated by the interaction of calnexin and monoglucosylated oligosaccharides does not necessarily require cycles of reglucosylation and deglucosylation. The gls2 and alg6 double mutant cells grown in the absence of exogenous stress show an induction of the binding protein (BiP)-encoding mRNA. An incubation of intact gls2 and alg6 mutant cells with [(14)C]glucose for 15 minutes in the absence of 1-deoxynojirimycin (DNJ) leads to the production of protein-linked Glc(1)Man(9)GlcNAc(2), Man(9)GlcNAc(2) and Man(8)GlcNAc(2). Belongs to the glycosyl hydrolase 31 family.