Used as a substrate in enzymatic assays to detect and measure the activity of β-galactosidase enzymes. This chemical is particularly valuable in molecular biology and biochemistry research, where it helps identify and quantify enzyme activity in various samples, including cell lysates and purified enzyme preparations. The enzymatic cleavage of the galactoside bond releases a chromogenic product, which can be easily measured spectrophotometrically, making it a useful tool for high-throughput screening and diagnostic applications. Additionally, it is employed in studying gene expression and regulation, especially in systems where β-galactosidase is used as a reporter gene.