Calpain Inhibitor I

Calpain inhibitor I is a synthetic tripeptide aldehyde that acts as a potent inhibitor of cysteine proteases including calpain I (K_i = 190 nM), calpain II (K_i = 220 nM), cathepsin B (K_i = 150 nM), and cathepsin L (K_i = 500 pM).¹ At 10-100 μM calpain inhibitor I dose-dependently prevents the degradation of IκBα and IκBβ by the ubiquitin-proteasome complex, which blocks activation of NFκB and the production of TNF and IL-1β, suggesting a potential therapeutic effect for inflammatory diseases.² At 10 μM, calpain inhibitor I can inhibit nitric oxide production by activated macrophages by interfering with transcription of the inducible nitric oxide synthase gene.³

WARNING This product is not for human or veterinary use.

1. Sasaki, T., Kishi, M., Saito, M., et al. Inhibitory effect of di- and tripeptidyl aldehydes on calpains and cathepsins. J. Enzyme Inhib. 3(3), 195-201 (1990).

2. Haas, M., Page, S., Page, M., et al. Effect of proteasome inhibitors on monocytic IκB-α and -β depletion, NF-κB activation, and cytokine production. J. Leukoc. Biol. 63(3), 395-404 (1998).

3. Griscavage, J.M., Wilk, S., and Ignarro, L.J. Serine and cysteine proteinase inhibitors prevent nitric oxide production by activated macrophages by interfering with transcription of the inducible NO synthase gene. Biochem. Biophys. Res. Commun. 215(2), 721-729 (1995).