Ac-IETD-pNA is a chromogenic substrate used in biochemical research to study caspase-8 activity, a key enzyme in apoptosis. It is cleaved by caspase-8, releasing p-nitroaniline, which produces a measurable color change for accurate enzyme activity quantification via spectrophotometry. This aids in understanding programmed cell death mechanisms, crucial for research on cancer and neurodegenerative diseases. It is also employed in drug development to screen potential inhibitors or activators of caspase-8.