Peptide-fluoromethyl ketone inhibitor ofCaspase-6. The CH2F or FMK (fluoromethyl ketone) inhibitor has several advantages over other types of derivatives: Penetrates cell membranes, Not toxic to cells, Irreversible inhibition.
Caspase-6 (also known as Mch2) is a member of the caspase family of cysteine proteases involved in apoptosis. It is a member of the Group III caspases (6, 8, and 9) which prefer the (L/V)EXD sequence as a substrate. Caspase-6 prefers a hydrophobic amino acid at P4, along with caspases-1 and -4, as opposed to the preference for Asp seen with caspases-2, -3, and -7. This is at odds with the gene sequence alignment that predicts Caspase-6 is more closely related to caspases-3 and -7 than to caspase-1. The preference by Caspase-6 for ?-branched amino acids in P4 fits well with the one known natural substrate, lamin A, and distinguishes it from caspases-1 and -4. Reconstitution experiments indicate that Caspase-6 activates caspases-3 and -7 and is therefore part of the proteolytic cascade that initiates apoptosis.
Very strong Inhibition of Caspase-6. Weak inhibition of Caspase-1 and Caspase-3, very weak inhibition of Caspase-7 and Caspase-8.
Dissolve Caspase-6 Inhibitor in high purity (>99.9%) DMSO before use.

For use on intact cells:
1. Prepare desired concentrated stock solutions as follows:
1 mg Z-VEID-FMK
in 7μl DMSO = 20 mM
in 15μl DMSO = 10 mM
in 30μl DMSO = 5 mM, etc.

2. Add 2 μL of above stock solution to 1 mL culture medium containing cells such that the fμl DMSO concentration is 0.2%. Levels of DMSO above this may cause some cellular toxicity, thus masking the effect of the protease inhibitor. Adding 2 μL of a 10 mM stock solution to 1 mL of culture medium gives a final Z-VEID- FMK concentration of 20 μM.
IMPORTANT NOTE for in vitro use: Our peptide inhibitors are synthesized as methyl esters to enhance cell permeability. In intact cells, the methyl groups are removed by endogenous enzymes. For in vitro experiments with purified enzymes, however, the methyl groups must first be removed by treating the inhibitor with esterase. A procedure is available upon request.