PROSITE documentation PDOC00127
Ubiquitin carboxyl-terminal hydrolases family 1 cysteine active site


Ubiquitin carboxyl-terminal hydrolases (EC (UCH) (deubiquitinating enzymes) [1,2] are thiol proteases that recognize and hydrolyze the peptide bond at the C-terminal glycine of ubiquitin. These enzymes are involved in the processing of poly-ubiquitin precursors as well as that of ubiquinated proteins.

There are two distinct families of UCH. The first class consist of enzymes of about 25 Kd and is currently represented by:

  • Mammalian isozymes L1, L3 and L5.
  • Yeast YUH1.
  • Drosophila Uch.

One of the active site residues of class-I UCH [3] is a cysteine. We derived a signature pattern from the region around that residue.


These proteins belong to family C12 in the classification of peptidases [4,E1].

Last update:

December 2001 / Text revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

UCH_1, PS00140; Ubiquitin carboxyl-terminal hydrolase family 1 cysteine active-site  (PATTERN)


1AuthorsJentsch S. Seufert W. Hauser H.-P.
TitleGenetic analysis of the ubiquitin system.
SourceBiochim. Biophys. Acta 1089:127-139(1991).
PubMed ID1647207

2AuthorsD'andrea A. Pellman D.
SourceCrit. Rev. Biochem. Mol. Biol. 33:337-352(1998).

3AuthorsJohnston S.C. Larsen C.N. Cook W.J. Wilkinson K.D. Hill C.P.
TitleCrystal structure of a deubiquitinating enzyme (human UCH-L3) at 1.8 A resolution.
SourceEMBO J. 16:3787-3796(1997).
PubMed ID9233788

4AuthorsRawlings N.D. Barrett A.J.
TitleFamilies of cysteine peptidases.
SourceMethods Enzymol. 244:461-486(1994).
PubMed ID7845226


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