The protein encoded by this gene belongs to the peptidase C12 family. This enzyme is a thiol protease that hydrolyzes a peptide bond at the C-terminal glycine of ubiquitin. This gene is specifically expressed in the neurons and in cells of the diffuse neuroendocrine system. Mutations in this gene may be associated with Parkinson disease.[provided by RefSeq, Sep 2009],catalytic activity: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).,disease:Oxidation of Met-1, Met-6, Met-12, Met-124 and Met-179 to methionine sulfoxide, and oxidation of Cys-220 to cysteine sulfonic acid have been observed in brains from Alzheimer disease (AD) and Parkinson disease (PD) patients. In AD, UCHL1 was found to be associated with neurofibrillary tangles.,function:Ubiquitin-protein hydrolase involved both in the processing of ubiquitin precursors and of ubiquitinated proteins. This enzyme is a thiol protease that recognizes and hydrolyzes a peptide bond at the C-terminal glycine of ubiquitin. Also binds to free monoubiquitin and may prevent its degradation in lysosomes. The homodimer may have ATP-independent ubiquitin ligase activity.,miscellaneous:In contrast to UCHL3, does not hydrolyze a peptide bond at the C-terminal glycine of NEDD8.,online information:Ubiquitin carboxy-terminal hydrolase L1 entry,PTM:O-glycosylated.,similarity:Belongs to the peptidase C12 family.,subunit:Homodimer. Interacts with SNCA (By similarity). Interacts with COPS5.,tissue specificity:Found in neuronal cell bodies and processes throughout the neocortex (at protein level). Expressed in neurons and cells of the diffuse neuroendocrine system and their tumors. Weakly expressed in ovary.,