UBE1 catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation. It is responsible for the primary ubiquitin-protein isopeptide bond formation and is a critical component for the initiation of in vitro conjugation reactions. UBE1 activates ubiquitin by the ATP dependent adenylation of its C-terminal glycine carboxyl group. This ubiquitin residue is then linked to the sulphydryl side chain moiety of a cysteine residue within UBE1 by forming a high energy thiol ester bond, liberating free AMP. There are two active sites within the UBE1 molecule allowing it to accommodate two ubiquitin molecules at one time, with a new ubiquitin forming an adenylate intermediate as the previous one is transferred to the thiol site. The activated ubiquitin is then transferred to the lysine of target proteins via the E2/E3 conjugation cascade. Recombinant corresponding to full length human UBE1, active, fused to 6His-tagged at N-terminus, expressed by baculovirus in Sf21 insect cells. Molecular Weight: ~122kD Storage and Stability: Aliquot to avoid repeated freezing and thawing and store at -70C. Aliquots are stable for 6 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
