InterPro domain: IPR026874

Glucosidase II catalyses the sequential removal of two alpha-1,3-linked glucose residues in the second step of N-linked oligosaccharide processing. It is a heterodimer whose alpha subunit bears the glycosyl hydrolase active site, while its beta subunit role is controversial. The beta subunit has been reported to be involved in the solubility and stability of the heterodimeric enzyme, and in retaining the enzyme within the endoplasmic reticulum [ 1 ]. Other studies suggest that the beta subunit modulates N-Glycan trimming in both fission yeast and mammals [ 2 , 3 , 4 ].

1. The heterodimeric structure of glucosidase II is required for its activity, solubility, and localization in vivo. Glycobiology 10, 815-27
2. Yeast GTB1 encodes a subunit of glucosidase II required for glycoprotein processing in the endoplasmic reticulum. J. Biol. Chem. 281, 6325-33
3. A novel role for Gtb1p in glucose trimming of N-linked glycans. Glycobiology 19, 1408-16
4. Glucosidase II beta subunit modulates N-glycan trimming in fission yeasts and mammals. Mol. Biol. Cell 20, 3974-84