The E2 ubiquitin-conjugating enzyme acquires the activated ubquitin from the E1 ubiquitin-activating enzyme (EC 188.8.131.52) and binds it via a transthioesterification reaction to itself. In the human enzyme the catalytic center is located at Cys-87 where ubiquitin is bound via its C-terminal glycine in a thioester linkage.
Ube2J1-/- mice have reduced viability and fail to thrive early after birth. Male Ube2J1-/- mice are sterile due to a defect in late spermatogenesis. Removal of the cytoplasm is incomplete in Ube2J1-/- elongating spermatids, compromising the release of mature elongate spermatids into the lumen of the seminiferous tubule