Invitrogen offers the Fluorogenic Chitinase/N-Acetylglucosaminidase
Substrate ELF 97 N-acetylglucosaminide, ELF 97 NAG; catalogue number:
E22011, which is designed to allow spatially resolved detection of
enzyme activity on colony indicator plates and histochemical analysis
The Molecular probes handbook is an excellent assay review resource as
well as a plug for their own products. Its where as a technical adviser
I get a lot of my information from.