Isopeptidase T is a deubiquitinating enzyme and a member of the family of ubiquitin-binding proteins (UBPs). UBPs contain a catalytic core of approximately 300 amino acids located between conserved cysteine and histidine boxes. By searching an EST database for sequences with similarity to ISOT, Timms et al. (1998) identified a partial ISOT3 cDNA.
Northern blot analysis has shown that ISOT-3 is highly expressed in ovary and testes, low-level expression in six other tissues tested (Timms et al., 1998).