EC - Caspase-9

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IntEnz Enzyme Nomenclature


Accepted name:
Other names:
ICE-like apoptotic protease 6
apoptotic protease Mch-6
apoptotic protease-activating factor 3
Systematic name:



Caspase-9 is an initiator caspase, as are caspase-2 (EC, caspase-8 (EC and caspase-10 (EC [1]. Caspase-9 contains a caspase-recruitment domain (CARD) in its N-terminal prodomain, which plays a role in procaspase activation [1]. An alternatively spliced version of caspase-9 also exists, caspase-9S, that inhibits apoptosis, similar to the situation found with caspase-2 [1]. Phosphorylation of caspase-9 from some species by Akt, a serine-threonine protein kinase, inhibits caspase activity in vitro and caspase activation in vivo [1]. The activity of caspase-9 is increased dramatically upon association with the apoptosome but the enzyme can be activated without proteolytic cleavage [2,3]. Procaspase-3 is the enzyme's physiological substrate [2]. Belongs in peptidase family C14.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , MEROPS , UniPathway
Protein domains and families: PROSITE:PDOC00864
Structural data: CSA , EC2PDB


  1. Chang, H.Y. and Yang, X.
    Proteases for cell suicide: functions and regulation of caspases.
    Microbiol. Mol. Biol. Rev. 64: 821-846 (2000). [PMID: 11104820]
  2. Yin, Q., Park, H.H., Chung, J.Y., Lin, S.-C., Lo, Y.-C., da Graca, L.S., Jiang, X. and Wu, H.
    Caspase-9 holoenzyme is a specific and optimal procaspase-3 processing machine.
    Mol. Cell 22: 259-268 (2006). [PMID: 16630893]
  3. Boatright, K.M., Renatus, M., Scott, F.L., Sperandio, S., Shin, H., Pedersen, I.M., Ricci, J.-E., Edris, W.A., Sutherlin, D.P., Green, D.R. and Salvesen, G.S.
    A unified model for apical caspase activation.
    Mol. Cell 11: 529-541 (2003). [PMID: 12620239]
  4. Salvesen, G.S. and Boatright, K.M
    In: Barrett, A.J., Rawlings, N.D. and Woessner, J.F. (Eds.) Handbook of Proteolytic Enzymes, 2nd ed., Elsevier, London, 2004, 1296-1298

[EC created 2007]