EST

E-64d is an irreversible, membrane-permeable inhibitor of lysosomal and cytosolic cysteine proteases and has diverse biological activities. It is a synthetic analog of E-64 and prodrug form of E-64c that inhibits calpain and the cysteine proteases cathepsins F, -K, -B, -H, and -L. E-64d (20-200 μM) induces cell cycle arrest at the G₂/M phase in A431 human epidermoid carcinoma cells. It inhibits protease-resistant prion protein accumulation in scrapie-infected neuroblastoma cells with an IC₅₀ value of 0.5 μM. E-46d also inhibits entry of vesicular stomatitis virus (VSV) particles pseudotyped with severe acute respiratory syndrome coronavirus (SARS-CoV) or SARS-CoV-2 spike glycoprotein into Vero cells, an effect that is reduced by expression of the serine protease TMPRSS2.

ChEBI: An L-leucine derivative that is the amide obtained by formal condensation of the carboxy group of (2S,3S)-3-(ethoxycarbonyl)oxirane-2-carboxylic acid with the amino group of N-(3-methylb tyl)-L-leucinamide.

Moderately toxic by intraperitoneal route. An experimental teratogen. Experimental reproductive effects. Mutation data reported. Whenheated to decomposition it emits toxic fumes of NOx.