β-Mannosidase from Streptomyces coelicolor (EC 3.2.1.25) catalyzes the hydrolysis of terminal, non-reducing β-D-mannose residues in β-D-mannosides. This gene encodes a member of the glycoside hydrolase family 2. The encoded protein is localized in the lysosome and acts as the final exoglycosidase in the catabolic pathway of N-linked glycoprotein oligosaccharides. Mutations in this gene are associated with β-mannosidosis, a lysosomal storage disorder affecting several neurological systems.