Ubiquitin carboxyl-terminal hydrolase isozyme L5?is an?enzyme?that in humans is encoded by the?UCHL5gene. Protease that specifically cleaves 'Lys-48'-linked polyubiquitin chains. Deubiquitinating enzyme associated with the 19S regulatory subunit of the 26S proteasome. Putative regulatory component of the INO80 complex; however is inactive in the INO80 complex and is activated by a transient interaction of the INO80 complex with the proteasome via ADRM1.