Used as a chromogenic substrate in enzymatic assays, particularly for measuring the activity of serine proteases such as trypsin-like enzymes. Upon cleavage by the target enzyme, it releases p-nitroaniline, which produces a yellow color detectable at 405–410 nm, allowing for real-time monitoring of enzyme kinetics. Commonly employed in biochemical research and drug development to screen inhibitors or study enzyme mechanisms. Its specificity makes it suitable for assays involving coagulation factors and other proteolytic enzymes with trypsin-like specificity.