Selectively hydrolyzes GlcNAcbeta(1->4)GlcNAc (N,N'-diacetylchitobiose) and Gal-NAcbeta(1->4)GlcNAc, but not their C-2 epimers GlcNAcbeta(1->4)ManNAc or Gal-NAcbeta(1->4)ManNAc. However, hydrolyzes both GlcNAcbeta(1->6)GlcNAc and GlcNAcbeta(1->6)ManNAc (Ref.7). Part of the binary chitinolytic system. Involved in hydrolyzation of chitobiose and higher chito-oligomers (produced from cell wall chitin by endochitinases), thus contributing to the formation of germ tubes, fruit-bodies and septa during hyphenation (Probable). Hydrolyzes synthetic substrate p-nitrophenyl-beta-N-acetyl-D-glucosaminide (pNP-GlcNAc) (PubMed:17302431, PubMed:12723619, Ref.7). Hydrolyzes synthetic substrate p-nitrophenyl-beta-N-acetyl-D-galactosaminide (pNP-GalNAc) (PubMed:12723619). Hydrolyzes chromogenic substrate 4-nitrophenyl-2-acetamido-2-deoxyglucopyranoside (PubMed:21505251, PubMed:17509134, PubMed:29239122). Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. Activated by non-covalent binding of the propeptide to the catalytic domain (PubMed:15494009, PubMed:17302431, PubMed:29239122). The concentration of the propeptide is regulated in the endoplasmic reticulum and the propeptide thus regulates the amount of the active enzyme at various stages of the growth cycle (PubMed:17302431). The dimeric enzyme has about half of the maximal activity in the presence of one bound propeptide, but is fully active with two bound O-glycosylated propeptides (PubMed:15494009, PubMed:17302431). Inhibited by N-acetylglucosamine (NAG)-thiazoline (PubMed:17302431). Optimum pH is around 5 (PubMed:15494009, PubMed:17302431, PubMed:12723619). More stable at alkaline than acidic pH (PubMed:15494009, PubMed:12723619, PubMed:17509134). Stable below 45 degrees Celsius. Homodimer (PubMed:15494009, PubMed:17302431, PubMed:21505251, PubMed:17509134, PubMed:29239122). Oligosaccharide moieties may also take part in the dimerization. Dimerization is a pH-dependent reversible process (PubMed:17509134). The individual catalytic cores dimerize and the catalytic core of one subunit in the active dimer interacts with the propeptide of the second subunit (PubMed:29239122). The precursor of the propeptide is intracellularly processed in the endoplasmic reticulum by a dibasic peptidase, different from Kex2, removing Lys-97--Arg-101 from the precursor producing the activated propeptide (PubMed:17302431). The propeptide binds non-covalently to the catalytic domain (PubMed:15494009, PubMed:17302431, PubMed:21505251, PubMed:29239122). Propeptide binding is necessary for full activation of the enzyme, dimerization of the catalytic domain and secretion of the active enzyme (PubMed:15494009, PubMed:17302431). O-glycosylated (PubMed:15494009, PubMed:17302431, PubMed:29239122). O-glycosylation (O-mannosylation) at the C-terminus of the propeptide is necessary for full enzyme activity (PubMed:15494009). N-glycosylated (PubMed:15494009, PubMed:17302431, PubMed:21505251, PubMed:17509134, PubMed:29239122). N-glycosylation of the catalytic domain increases the stability and solubility of the enzyme, especially at low pH (PubMed:15494009, PubMed:17509134). Contains high mannose-type (M4-M11) N-glycans at the C-terminus (PubMed:15494009, PubMed:17509134, PubMed:29239122). N-glycan deglycosylation does not affect enzyme activity (PubMed:17509134). This enzyme can be used for synthesis of lacto-N-triose II (GlcNAcbeta1-3Galbeta1-4Glc), a major oligosaccharide component of human breast milk, and its positional isomer (GlcNAcbeta1-6lactose) from lactose and D-N-acetylglucosamine (GlcNAc) by reverse hydrolysis reaction (PubMed:12723619). This enzyme can also be used for selective large-scale removal of GlcNAcbeta(1->4)GlcNAc and GalNAcbeta(1->4)GlcNAc from mixtures containing them and their C-2 epimers GlcNAcbeta(1->4)ManNAc and GalNAcbeta(1->4)ManNAc in order to produce rare ManNAc-containing disaccharides that are important components of microbial cell walls, and can be utilized as immunoactive compounds (Ref.7). Utilized in the synthesis of beta-GalNAc-containing oligosaccharides beta-D-GalpNAc-(1->4)-alpha-D-GlcpNAcOAll and beta-D-GalpNAc-(1->6)-beta-D-Galp-(1->4)-alpha-D-GlcpNAcOAll (PubMed:12681926). The structural features make this enzyme suitable for biotechnological applications as it is very stable and has a robust framework. The solved three-dimensional structure will aid in designing engineered mutant enzyme variants with desired specificity and activity (PubMed:29239122). Belongs to the glycosyl hydrolase 20 family. According to PubMed:29239122 Asn-525 is not glycosylated in contrast to PubMed:17509134, which reports that all predicted N-glycosylation sequences are glycosylated.