4-Methylumbelliferyl a-D-glucosaminide is a fluorescent substrate used in enzyme diagnostics. It is a substrate for the bacterial enzymes ?-glucuronidase and ?-glucosidase, which are involved in the metabolism of drugs and other xenobiotics. 4-Methylumbelliferyl a-D-glucosaminide can be used to detect bacterial contamination in culture media and environmental samples, as well as food products.