Exo-type enzyme that specifically cleaves the non-reducing terminal glycosidic bond of chitooligosaccharides (PubMed:12923090, PubMed:15136574, PubMed:28130448). Catalyzes the hydrolysis of GlcN-GlcNAc to glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) (PubMed:15136574, PubMed:28130448). Involved in chitin degradation (PubMed:12923090, PubMed:15136574). Can also hydrolyze reduced chitobiose (GlcN2OH) and chitooligosaccharides of various chain lengths (PubMed:12923090). beta-D-glucosaminyl-(1->4)-N-acetyl-D-glucosamine + H2O = D-glucosamine + N-acetyl-D-glucosamine Optimum pH is 6.0 (with reduced chitobiose as substrate). Optimum temperature is 80 degrees Celsius (with reduced chitobiose as substrate). Glycan degradation; chitin degradation. Homodimer. Induced by GlcNAc(2). Also induced, to a lesser extent, by colloidal chitin. Belongs to the glycosyl hydrolase 35 family.