During apoptosis, activated caspase-3 cleaves several substrates, including poly(ADP-ribose) polymerase, which it specifically targets at the amino sequence DEVD. Ac-DEVD-pNA is a para-nitro aniline chromophore cleaved by caspases (Km = 18, 11, 32, 180, and 12 μM for caspases-1, -3, -4, -6, and -7, respectively). It is not cleaved by caspase-2. Cleavage is monitored colorimetrically at 405 nm.
![(4S)-4-[[(2S)-2-acetamido-3-carboxypropanoyl]amino]-5-[[(2S)-1-[[(2S)-3-carboxy-1-(4-nitroanilino)-1-oxopropan-2-yl]amino]-3-methyl-1-oxobutan-2-yl]amino]-5-oxopentanoic acid](https://www.chemicalbook.com/CAS/20180529/GIF/189684-50-2.gif)