Glucosidase, alpha neutral AB; Glucosidase II subunit beta (GANAB, PRKCSH, α-Glucosidase II)

Abstract

The synthesis of N-linked glycans is initiated by the synthesis of a Glc3Man9GlcNAc2 lipid-linked precursor and the co-translational transfer to nascent polypeptide chains in the lumen of the endoplasmic reticulum (ER) (Kornfeld and Kornfeld 1985). Immediately after transfer of the glycan to Asn side chains glucose (Glc), trimming is initiated by the cleavage of the terminal α1,2-Glc residue by α-glucosidase I (MOGS). Subsequent cleavage of the two internal α1,3-Glc residues is accomplished by the heterodimeric enzyme α-glucosidase II (GANAB/PRKCSH) (Burns and Touster 1982; Grinna and Robbins 1979, 1980) to produce the Man9GlcNAc2-Asn processing intermediate (Fig. 114.1).