Z-VDVAD-pNA is a colorimetric substrate for caspase-2.1 Caspase-2 binds to and cleaves the Val-Asp-Val-Ala-Asp (VDVAD) peptide sequence to release p-nitroanilide (pNA), which can be quantified by colorimetric detection at 405 nm as a measure of caspase-2 activity. Z-VDVAD-pNA can also be cleaved, with lower efficiency, by caspase-3 and -7.WARNING This product is not for human or veterinary use.