Caspase-9 is a member of the caspase family of cysteine proteases. Caspase-9 exists in cells as an inactive proenzyme. Proteolytic processing of this inactive proenzyme generates the large and small subunits which, when assembled as a tetramer (a pair of heterodimers), form the active caspase. Cascades of caspase activation have been shown to be the key signal-transducing events in apoptosis. Caspase-9 is considered to be an upstream enzyme that initiates caspase cascade leading to apoptosis. The recombinant Procaspase-9 is produced by expression of a human cDNA in E. coli and further purified by multiple chromatographic steps.
