Hydrolase that can remove conjugated ubiquitin from proteins and may therefore play an important regulatory role at the level of protein turnover by preventing degradation (By similarity). Has a role in meiosis. 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).