Suc-YVAD-pNA is a colorimetric substrate for caspase-1/interleukin-1β-converting enzyme (ICE) and caspase-4.1 Caspase-1 and caspase-4 preferentially bind to and cleave the Tyr-Val-Ala-Asp (YVAD) peptide sequence to release p-nitroanilide (pNA), which can be quantified by colorimetric detection at 405 nm as a measure of caspase-1 and caspase-4 activity.
References
1. Margolin, N., Raybuck, S.A., Wilson, K.P., et al. Substrate and inhibitor specificity of interleukin-1β-converting enzyme and related caspases. J. Biol. Chem. 272(11), 7223-7228 (1997).