UBE2V1(Ubiquitin-conjugating enzyme E2 variant 1) is also named as CROC1, UBE2V, UEV1 and belongs to the ubiquitin-conjugating enzyme family. They have sequence similarity to other ubiquitin-conjugating enzymes but lack the conserved cysteine residue that is critical for the catalytic activity of E2s. Therefore, Uev1A does not have ubiquitin-conjugating activity in vitro. It is thought to be involved in the control of differentiation by altering cell cycle behavior. CROC1 transcripts in all human tissues examined, with highest levels in brain, skeletal muscle, and kidney.