Ubiquitination: In this step, ubiquitin is attached to the target protein. This process requires three types of enzymes: E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin ligase). Recognition and Binding: The polyubiquitinated protein is recognized by the proteasome, a large protease complex. Degradation: The protein is unfolded and translocated into the proteasome core, where it is degraded into small peptides and amino acids.
