Are R&D Systems Caspase Inhibitors irreversible?

Yes, the majority of R&D Systems Caspase Inhibitors have a Fluoromethyl ketone (FMK) functional group on the C-terminus of the peptide, and act as effective irreversible inhibitors with no added cytotoxic effects. Inhibitors synthesized with a benzyloxycarbonyl group (also known as BOC or Z) at the N-terminus and O-methyl side chains exhibit enhanced cellular permeability. R&D Systems also offers a General Caspase Inhibitor, Q-VD-OPh, Catalog # OPH001, as well as a FITC-conjugated pan-caspase inhibitor (ApoStat), Catalog # FMK012, which are both cell-permeable, irreversible inhibitors of caspase activity.

Does R&D Systems offer a negative control for Caspase Inihibitors with benzyloxycarbonyl group (Z-) at the N-terminus and the FMK functional group at the C-terminus?

Yes, R&D Systems offers Caspase Inhibitor Control Z-FA-FMK, Catalog # FMKC01, which is an inhibitor of cathepsins B and L but not caspases, and has been used in several systems as a negative control for peptide inhibitors of caspases.

May we ask the MW difference between the active form and the proform of Caspase 8 while performing WB?

In treated cells induced to undergo apoptosis, caspase-8 migrates as a 55/53 kDa (pro-form), 41/42 kDa (a cleaved/active or intermediate form), and 18 kDa (active form). The proform (55/53 kDa) is still seen in treated cells because not all cells undergo apoptosis at once.

Caspase-8 Inhibitor Z-IETD-FMK

Name: Caspase-8 Inhibitor Z-IETD-FMK
Brand: R&D Systems
SKU: FMK007

R&D Systems, part of Bio-Techne | Catalog # FMK007

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Background
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Key Product Details

Cell permeable fluoromethyl ketone (FMK)-derivatized peptides act as effective irreversible Caspase inhibitors with no cytotoxic effects and, therefore, are useful tools for studying Caspase activity.

Conjugate

Unconjugated

View all Caspase-8 Small Molecules and Peptides »

Formulation, Preparation and Storage

FMK007

Shipping	The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage	Store the unopened product at -20 to -70 °C. Use a manual defrost freezer and avoid repeated freeze-thaw cycles. Do not use past expiration date.

Background: Caspase-8

Caspase-8, also known as MCH5, FLICA and MACH alpha 1, is a 28 kDa member of the peptidase C14A family of enzymes. It is widely expressed and is considered an initiating caspase for the apoptotic cascade. Caspase-8 acts on a wide variety of substrates including Pro-Caspases-3, -4, -6, -7, -9 and -10, c-FLIPL and Pro-Caspaseâ€‘8 itself. Caspase-8 is recruited to the death-inducing signaling complex (DISC) that forms around the death domains of the oligomerized receptors. Multiple rounds of cleavage generate Caspase-8 p10 and p18 which heterodimerize and then associate into the active tetrameric enzyme containing two p10 and two p18 subunits.

Alternate Names

CASP8, Caspase8, Mch5

Entrez Gene IDs

841 (Human); 12370 (Mouse)

Gene Symbol

CASP8

Additional Caspase-8 Products

Product Documents for Caspase-8 Inhibitor Z-IETD-FMK

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Product Specific Notices for Caspase-8 Inhibitor Z-IETD-FMK

For research use only

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