Ubiquitin-activating enzyme (E1)

Ubiquitin-activating enzyme (E1) is a crucial protein involved in the process of tagging other proteins for various cellular functions, such as degradation or signaling. E1's role is to activate ubiquitin, a small regulatory protein, by attaching it in an energy-dependent step using ATP. Once activated, ubiquitin is transferred to a ubiquitin-conjugating enzyme (E2), which then helps attach ubiquitin to specific target proteins. This process ensures precise control over protein lifespan and activity, maintaining cellular health and function.