Ubiquitin-Activating Enzymes

**Definition:** A class of enzymes that catalyzes the ATP-dependent formation of a thioester bond between itself and UBIQUITIN. It then transfers the activated ubiquitin to one of the UBIQUITIN-PROTEIN LIGASES.

**Tree numbers:** - D08.811.464.938.249

**Synonyms:** - Ubiquitin-Activating Enzyme - Ubiquitin-Activating Enzyme E1 - Ubiquitination Activating Enzyme E1