Description_x000D_ Application_x000D_ 4-Nitrophenyl N,N′-diacetyl-β-D-chitobioside has been used to measure the exochitinase activity of DOI, a novel protein from Chinese yam (Dioscorea opposita Thunb.) and exochitinase activity of ChiEn3 from Coprinopsis cinerea. It has also been used to determine the activity of a chitinolytic enzyme, N-acetyl-β-D-glucosaminidases._x000D_ Packaging_x000D_ 10 mg in poly bottle_x000D_ 5 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ 4-Nitrophenyl N,N′-diacetyl-β-D-chitobioside is a substrate for determining exochitinase activity (chitobiosidase activity).