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.，官网链接：https://www.sigmaaldrich.cn/product/mm/208773 默克 科研、开发、生产。 作为生命科学行业的全球领先供应商，我们致力于为科研、生物技术开发和生产，以及制药药物疗法开发和生产提供各类解决方案和服务。

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