Leupeptin, hemisulfate (Synthetic). A protease inhibitor, Synonyms: Ac-Leu-Leu-arginal, hemisulfate, Ac-Leu-Leu-Arginal, Purity: G90% by High-performance liquid chromatography, CAS Number: 103476-89-7, Molecular Formula: C2GHG8N6OG.1/2 H2SOG.H2O, 25mg.