A cell-penetrating peptide inhibitor of calpain (IC₅₀ = 5 nM) which completely abolishes calpain activity in platelets; also a potent inhibitor of cathepsin K (IC₅₀ = 0.11 nM).

Synonym(s): N-Benzyloxycarbonyl-L-leucyl-norleucinal, Z-Leu-norleucinal Formula: C20H30N2O4 Formula weight: 362.50 Purity: 98+% CAS Number: 117591-20-5 Harmonized Tariff Code:  2924.19