Small-molecule inhibitor: ZVAD-FMK

Name

History: As described by van Noorden (2001) the development of zVAD-fmk, in a commercial setting, was driven by R. E. Smith, about 1995. It then became perhaps the most widely-used of the general inhibitors of caspases, or pan-caspase inhibitors.
Peptidases inhibited: Probably, all peptidases in family C14 are inhibited. Half-times (s) for inhibition at 1 micromolar inhibitor (Salvesen & Nagase, 2001) are: 2.5 (caspase-1), 2400 (caspase-2), 43 (caspase-3), 130 (caspase-4), 5.3 (caspase-5), 98 (caspase-6), 39 (caspase-7), 2.5 (caspase-8) and 3.9 (caspase-9). zVAD-fmk has also been reported to inhibit cathepsin B and cathepsin H (Schotte et al., 1999) and rhinovirus picornain 2A (Deszcz et al., 2006). Inhibition of peptide:N-glycanase may also be significant (Misaghi et al., 2006).
Mechanism: Inhibition is irreversible, by reaction with the active site cysteine.
Pharmaceutical relevance: zVAD-fmk would not be suitable for drug use because its metabolism gives rise to the toxic fluoroacetate (van Noorden, 2001).

CID at PubChem: 5497173
Structure
Formula weight: 467
Related inhibitors: The "VAD" tripeptide has been combined with "warheads" other than fluoromethyl ketone. An example of one of the resulting compounds is z-VAD-dcb (2-valyl-alanyl-3(S)-3-amino-4-oxo-5-(2,6-dichlorobenzoyloxopentanoic acid: Loddick et al., 1996).

Inhibitor class: This compound is of the halomethylketone class of cysteine peptidase inhibitors. Both chloro- and fluoromethylketones inhibit cysteine peptidases, and the fluoromethylketones are generally specific for cysteine peptidases. These compounds are activated ketones that form tetrahedral adducts at the active site, and may go on to react covalently, forming thioethers with the active site cysteine. The halomethylketones have been reviewed by Powers et al. (2002), pp. 4646 - 4656, and Yin et al. (2006).
Comment: zVAD-fmk has been widely used as a cell permeant inhibitor of caspases generally. The methyl ester is presumably a pro-form of the inhibitor.