Proteasome Inhibitor XXI, Z-LLLL-SF

A cell-permeable tetrapeptidylsulfonylfluoride-based irreversible proteasome inhibitor that selectively inhibits the hydrolysis of Suc-LLVY-AMC (Cat. No. 539142) by the β5 chymotrypsin-like activity (IC₅₀ = 7 nM using yeast 20S proteasome), while exhibiting much reduced potency against Z-LLE-AMC (Cat. No. 539141) hydrolysis by the β1 caspase-like activity or Z-LLR-AMC hydrolysis by the β2 trypsin-like activity (29% and 75% inhibition, respectively, with 200 µM inhibitor). One hour inhibitor treatment at 5 µM in HEK cultures is shown to completely abolish β5 labeling by the proteasome probe MV151, while only partial MV151 blockage is seen with β1 and β2 at an inhibitor concentration of 50 µM.

Please note that the molecular weight for this compound is batch-specific due to variable water content. Please refer to the vial label or the certificate of analysis for the batch-specific molecular weight. The molecular weight provided represents the baseline molecular weight without water.

Cell permeable: yes

Primary Target
β5 chymotrypsin-like activity of 20S proteasome

Reversible: no

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C. Stock solutions are stable for up to 6 months at -20°C.

Brouwer. A.J., et al. 2013. J. Med. Chem.55, 10995.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)