Used as a substrate in enzymatic assays to study the activity of proteases, particularly chymotrypsin-like enzymes. It helps in detecting and quantifying enzyme activity by measuring the release of p-nitroaniline (pNA), which produces a yellow color detectable at 405 nm. This makes it valuable in biochemical research for understanding enzyme kinetics and inhibitor screening. Additionally, it aids in the development of therapeutic agents targeting protease-related diseases.