Description General description The non-permeant fluorogenic Calpain Substrate III (Cat. No. 208771) is made cell-permeable by a c-terminal heptaarginine extension via a Glu linkage. In addition to the expected improvement in permeability, the modified peptide also exhibits enhanced Calpain B sensitivity (kcat = 0.2 s-1, kcat/KM = 5000 M-1 s-1) when compared to the parental peptide (kcat = 0.17 s-1, kcat/KM = 680 M-1 s-1). Its suitability in detecting cellular Ca2+-dependent calpain activity is demonstrated both in intact Drosophila melanogaster S2 cells following ionomycin stimulation and in S2 lysates via direct Ca2+ addition. The non-permeant fluorogenic Calpain Substrate III (Cat. No. 208771) is made cell-permeable by a c-terminal heptaarginine extension via a Glu linkage. In addition to the expected improvement in permeability, the modified peptide also exhibits enhanced Calpain B sensitivity (kcat = 0.2 s-1, kcat/KM = 5000 M-1 s-1) when compared to the parental peptide (kcat = 0.17 s-1, kcat/KM = 680 M-1 s-1). Its suitability in detecting cellular Ca2+-dependent calpain activity is demonstrated both in intact Drosophila melanogaster S2 cells following ionomycin stimulation and in S2 lysates via direct Ca2+ addition. The non-permeant fluorogenic Calpain Substrate III is made cell-permeable by a c-terminal heptaarginine extension via a Glu linkage. Packaging Packaged under inert gas Warning Toxicity: Standard Handling (A) Sequence (DABCYL)-Thr-Pro-Leu-Lys~Ser-Pro-Pro-Pro-Ser-Pro-Arg-Glu(EDANS)-Arg-Arg-Arg-Arg-Arg-Arg-Arg-NH₂ Physical form Supplied as a trifluoroacetate salt Reconstitution Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C. Other Notes Banoczi, Z., et al. 2008. Bioconjug. Chem.19, 1375.