Has hexosaminidase activity. 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 (PubMed:27149221). 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) (By similarity). Inhibited by galacto-NAG-thiazoline (PubMed:27149221). kcat is 79.3 min(-1), 30.4 min(-1), 122 min(-1) and 92.4 min(-1) for PNP-GalNAc, PNP-GlcNAc, 3F4NP-GalNAc and 3F4NP-GlcNAc, respectively. Optimum pH is 6.7. Homodimer; disulfide-linked. Expressed in synovial fibroblasts and synovial membranes. Expression is inhibited by TGFB1. Belongs to the glycosyl hydrolase 20 family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus.