Used as a fluorogenic substrate in enzymatic assays to detect β-galactosidase activity. Upon enzymatic hydrolysis, it releases a fluorescent compound, 4-methylumbelliferone, enabling real-time monitoring of enzyme activity in cell cultures, lysates, and histochemical staining. Commonly applied in molecular biology for reporter gene assays, especially in transfection and gene expression studies. Also utilized in microbiology to detect lactose-fermenting organisms and in high-throughput screening due to its sensitive fluorescence signal.