Cleaves alpha 1,2-, alpha 1,3-, and alpha 1,6-linked mannose residues from glycoproteins. Involved in the degradation of free oligosaccharides in the cytoplasm. Hydrolysis of terminal, non-reducing alpha-D-mannose residues in alpha-D-mannosides. Inhibited by 1,4-dideoxy-1,4-imino-d-mannitol (DIM) and EDTA. Expressed in kidney and liver (at protein level) (PubMed:24550399). Widely expressed, with highest levels in lung, ovary and testis (PubMed:16904268). Also detected at lower levels in heart, brain, liver, spleen, kidney and thymus (PubMed:16904268). Viable and fertile with no gross defects. Loss of neutral mannosidase activity leading to accumulation of free higher-order oligosaccharides such as Man(8-9)GlcNAc(1) in many organs, particularly liver and heart. Tissues show histopathological changes with strongest defects observed in liver, small intestine, kidney and central nervous system (CNS). In liver, hepatocytes appear swollen with increased levels of glycogen and accumulation of lipid droplets. In the small intestine, enterocytes accumulate glycogen apically and also develop vacuoles in the basal cell region. In the CNS, neurons in isocortex lamina V show signs of degeneration with formation of vacuoles in basal cell regions. Vacuolation is also found in glial cells of white matter tracts. In kidney, there are signs of fibrosis along Bowman's capsule and a small number of glomeruli appear to be collapsed. Belongs to the glycosyl hydrolase 38 family.