Not available outside of the UK & Ireland.

Application

Useful in conjunction with E1 and E2 for the study of enzyme kinetics, screening inhibitors, and selectivity profiling.

Biochem/physiol Actions

XIAP (X-linked inhibitor of apoptosis) is the most potent caspase-interacting protein and inhibits both intrinsic and extrinsic pathways of apoptosis. Its up-regulation in tumor cells is linked with resistance to chemotherapy. In inflammatory breast cancer (IBC) this protein is linked with resistance to antibody-dependent cellular cytotoxicity (ADCC) driven by cetuximab and trastuzumab. Embelin, an inhibitor of XIAP, functions as an anti-tumor agent in myeloma cell line (HL-60) by suppressing the expression of XIAP. Elevated expression of XIAP in rectal cancer is associated with chemotherapy resistance.

General description

XIAP (X-linked inhibitor of apoptosis) is an anti-apoptotic protein belonging to the inhibitor of apoptosis protein (IAP) family, an evolutionary conserved protein family. XIAP contains three tandem copies of BIR (baculovirusIAP repeat) domain, which is composed of ∼70 residues. IAP family members also contain a RING (really interesting new gene) zinc finger domain in their C-terminals.

Physical form

Formulated in 25 mM Tris-HCl, pH 8.0, 100 mM NaCl, 0.05% Tween-20, 100 µg/ml FLAG peptide, 20% glycerol, and 3 mM DTT.

Preparation Note

Thaw on ice. Upon first thaw, briefly spin tube containing enzyme to recover full content of the tube. Aliquot enzyme into single use aliquots. Store remaining undiluted enzyme in aliquots at -70°C. Note: Enzyme is very sensitive to freeze/thaw cycles.

Unit Definition

One unit is defined as the amount of enzyme required to transfer 1 pmol of ubiquitin to substrate/min at 37°C.