Necessary for the catabolism of N-linked carbohydrates released during glycoprotein turnover. Cleaves all known types of alpha-mannosidic linkages. Hydrolysis of terminal, non-reducing alpha-D-mannose residues in alpha-D-mannosides. Binds 1 zinc ion per subunit. First processed into 3 peptides of 70 kDa, 42 kDa (D) and 13/15 kDa (E). The 70 kDa peptide is further processed into three peptides (A, B and C). The A, B and C peptides are disulfide-linked. Heavily glycosylated. The disease is caused by variants affecting the gene represented in this entry. Belongs to the glycosyl hydrolase 38 family. Truncated N-terminus. Truncated N-terminus. Leiden Open Variation Database (LOVD)