ENZYME

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ENZYME entry: EC 3.4.22.62

Accepted Name

Caspase-9.

Alternative Name(s)

APAF-3.

Apoptotic protease Mch-6.

Apoptotic protease-activating factor 3.

CASP-9.

ICE-LAP6.

ICE-like apoptotic protease 6.

Reaction catalysed

Strict requirement for an Asp residue at position P1 and with a marked preference for His at position P2. It has a preferred cleavage sequence of Leu-Gly-His-Asp-|-Xaa

Comment(s)

Caspase-9 is an initiator caspase, as are caspase-2 (EC 3.4.22.55), caspase-8 (EC 3.4.22.61) and caspase-10 (EC 3.4.22.63).
Contains a caspase-recruitment domain (CARD) in its N-terminal prodomain, which plays a role in procaspase activation.
An alternatively spliced version of caspase-9 also exists, caspase- 9S, that inhibits apoptosis, similar to the situation found with caspase-2.
Phosphorylation of caspase-9 from some species by Akt, a serine- threonine protein kinase, inhibits caspase activity in vitro and caspase activation in vivo.
The activity of caspase-9 is increased dramatically upon association with the apoptosome but the enzyme can be activated without proteolytic cleavage.
Procaspase-3 is the enzyme's physiological substrate.
Belongs to peptidase family C14.

Cross-references

PROSITE

BRENDA

EC2PDB

ExplorEnz

PRIAM enzyme-specific profiles

3.4.22.62

KEGG Ligand Database for Enzyme Nomenclature