Has hexosaminidase activity (PubMed:19040401). Responsible for the cleavage of the monosaccharides N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) from cellular substrates. Has a preference for galactosaminide over glucosaminide substrates (By similarity). Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. Inhibited by O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino N-phenylcarbamate (PUGNAc). Inhibited by galacto-NAG-thiazoline (By similarity). Optimum pH is 5.5. Optimum temperature is 37 degrees Celsius. Homodimer; disulfide-linked. Ubiquitous. Belongs to the glycosyl hydrolase 20 family. Truncated N-terminus.