Interleukin-1 β converting enzyme (EC 22.214.171.124) (ICE) [1,2] is responsible
for the cleavage of the IL-1 β precursor at an Asp-Ala bond to generate the
mature biologically active cytokine. ICE a thiol protease composed of two
subunits of 10 (p10) and 20 Kd (p20), both derived by the autocleavage of a 45
Kd precursor (p45). Two residues are implicated in the catalytic mechanism: a
cysteine and an histidine. They are located in the P20 subunit after cleavage
of the precursor. ICE belongs to a family of peptidases  which is
implicated in programmed cell death (apoptosis) and which has been termed
'caspase' for cysteine aspase. ICE is known as Caspase-1 and the other members
of this family  are:
Caspase-2 (ICH-1, NEDD-2).
Caspase-3 (also known as apopain, CPP32, Yama), a protease which, at the
onset of apoptosis, proteolytically cleaves poly(ADP-ribose) polymerase
(see <PDOC00360>) at an Asp-Gly bond.
Caspase-4 (ICH-2, TX, ICErel-II).
Caspase-5 (ICH-3, TY, ICErel-III).
Caspase-7 (MCH-3, ICE-LAP3, CMH-1, SCA-2, LICE2).
Caspase-8 (MCH-5, MACH, FLICE).
Caspase-9 (MCH-6, ICE-LAP6).
Caspase-10 (MCH-4, FLICE2).
Caenorhabditis elegans ced-3 involved in the initiation of apoptosis.
We have developed signature patterns for both active site residues. We also
developed two profiles, one specific for the caspase P10 subunit and one for
the caspase P20 subunit.
These proteins belong to family C14 in the classification of peptidases
December 2004 / Patterns and text revised.
PROSITE methods (with tools and information) covered by this documentation:
Thornberry N.A., Molineaux S.M.
Interleukin-1 beta converting enzyme: a novel cysteine protease required for IL-1 beta production and implicated in programmed cell death.
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