Widely used in enzymatic assays to measure the activity of proteolytic enzymes, particularly elastase, a serine protease. The compound acts as a chromogenic substrate — upon cleavage by the enzyme, it releases p-nitroaniline, which is yellow and can be easily detected by spectrophotometry at around 410 nm. This color change allows for real-time monitoring of enzyme kinetics, making it valuable in biochemical research, drug development, and screening of enzyme inhibitors. Its high specificity for elastase makes it suitable for diagnostic applications and studies of enzyme mechanism and specificity.