The Ubiquitination Process

Ubiquitination is an important post-translational modification that modulates many biological processes, including protein degradation, immune responses, and protein localization. During the process of ubiquitination, proteins are covalently modified with a single ubiquitin and poly-ubiquitin chains through a specific isopeptide bond. The ubiquitination process has three main steps: ubiquitin activation, ubiquitin conjugation, and ubiquitin ligation, which are catalyzed by ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3), respectively. Here the chemistry and the biochemical mechanism of the ubiquitination process is discussed.