Biochem/physiol Actions

Useful in screening caspase inhibitors, studying enzyme kinetics and regulation, determining target substrates, as well as serving as positive controls in caspase activity assays and Western blot analysis.

Caspase 4 is an inflammatory caspase associated with innate immune responses. It plays a key role in the endoplasmic reticulum (ER) stress-induced apoptosis. Caspase 4 mediates the fusion of phagosomes containing pathogens with the lysosome. It inhibits pathogen replication, development, and production of pro-inflammatory cytokines. Caspase 4 induces caspase activation and pyropoptotic death by binding to the intracellular lipopolysaccharide (LPS) of the Gram-negative bacterial outer membrane. This is mediated by the highly specific caspase recruitment domain (CARD).

General description

The caspase 4 (CASP4) gene is mapped to human chromosome 11q21. Caspase 4 is a cysteine-aspartic protease, localized to the outer membrane of the endoplasmic reticulum (ER). The N-terminus of the enzyme contains a caspase recruitment domain (CARD).

Physical form

Solution in 0.052% ammonium chloride, 0.158% Tris−HCl, and 0.76% sodium chloride

Unit Definition

One unit will hydrolyze 1 nmol of the caspase substrate WEHD-pNA to WEHD and p-nitroaniline per hour at pH 7.2 at 37 °C.