Reaction: Thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal)
Other names: ubiquitin C-terminal hydrolase; yeast ubiquitin hydrolase
Comments: Links to polypeptides smaller than 60 residues are hydrolysed more readily than those to larger polypeptides. Isoforms exist with quantitatively different specificities, amongst the best known being UCH-L1 and UCH-L3, which are major proteins of the brain of mammals [1]. Inhibited by ubiquitin aldehyde (in which Gly76 is replaced by aminoacetaldehyde). Ubiquitinyl hydrolase 1 is the type example of peptidase family C12, with a similar protein fold to papain and catalytic amino acids Cys, His and Asp. There is a separate family (C19) of enzymes that also hydrolyse ubiquitinyl bonds, and it is thought that all the ubiquitinyl hydrolases are also ubiquitin thiolesterases (EC 3.1.2.15)
Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 86480-67-3 and 189642-63-5
References
1. Johnston, S.C., Larsen, C.N., Cook, W.J., Wilkinson, K.D. and Hill, C.P. Crystal structure of a deubiquitinating enzyme (human UCH-L3) at 1.8Å resolution.EMBO J. 16 (1997) 3787-3796. [PMID: 9233788]
2. Wilkinson, K.D. Ubiquitin C-terminal hydrolase. In: Handbook of Proteolytic Enzymes, (Barrett, A.J., Rawlings, N.D. and Woessner, J.F. eds), pp. 470-472 (1998) Academic Press, London