Description
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. 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)