UCHL1 (Ubiquitin Carboxy-terminal Hydrolase L1) (human) (rec.)

Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) is a deubiqutinating enzyme. Ubiquitin UCHL1, also known as PGP9.5, is a protein of 223 amino acids and one of the most abundant proteins in the brain (1~2% of the total soluble protein). Although it was originally characterized as a deubiquitinating enzyme recent studies indicate that it also functions as a ubiquitin (Ub) ligase and a mono-Ub stabilizer. A large amount of mono-Ub is tightly associated with UCHL1, inhibiting the degradation of mono-Ub in the brain. The precise regulation of UCHL1 is essential for neurons to survive and to maintain their proper function. UCHL1 is involved in the pathogenesis of Parkinson’s disease (PD) and Alzheimer's disease (AD). Down-regulation and extensive oxidative modification of UCHL1 have been observed in the brains of AD patients as well as PD patients. A post-translational modification of UCHL1 that controls the function of UCHL1 is mono-ubiquitination. It occurs reversibly to a lysine residue near the active site of UCHL1.