Human recombinant Ubiquitin Activating Enzyme E1

UBE1, the ubiquitin activating enzyme, is the first enzyme utilized in the pathway to conjugate ubiquitin onto target substrates through an ubiquitin-protein isopeptide bond. The C-terminal glycine of an ubiquitin (G76) is initially adenylated in an ATP dependent manner activating it so it can be transferred to the active site cysteine of UBE1 forming an ubiquitin-UBE1 thiolester. With the help of the other enzymes in the ubiquitin conjugation pathway (E2/E3 enzymes) the ubiquitin is transferred to a specific lysine on a target substrate.