Background：UBE1(Ubiquitin-activating enzyme E1) is also named as A1S9T, UBE1 and belongs to the ubiquitin-activating E1 family. It catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation and initiates the activation and conjugation of ubiquitin-like proteins. Defects in UBE1 are the cause of spinal muscular atrophy X-linked type 2(SMAX2).
