Used as a chromogenic substrate in enzymatic assays, particularly for measuring the activity of serine proteases such as trypsin-like enzymes. The presence of the p-nitroanilide group allows for easy detection of enzyme activity through the release of yellow-colored p-nitroaniline upon cleavage, which can be monitored spectrophotometrically at around 405 nm. Commonly employed in kinetic studies and inhibitor screening due to its high specificity and sensitivity. Also utilized in diagnostic applications to assess protease levels in biological samples.