Proteasome 20S Catalytic Core Subunit (20S Proteasome)

The Proteasome 20S catalytic core subunit is a central component of the proteasome complex, responsible for regulated protein degradation in eukaryotic cells. The 20S core particle (CP) forms the heart of the larger 26S proteasome and can also function independently. It is a barrel-shaped structure composed of four stacked heptameric rings, with two outer α-rings and two inner β-rings. The β-subunits contain threonine residues that act as nucleophiles in peptide bond hydrolysis, providing chymotrypsin-like, trypsin-like, and caspase-like enzymatic activities. The primary role is ATP-independent degradation of damaged or misfolded proteins and regulatory proteins no longer needed by the cell, maintaining protein homeostasis. Access to the catalytic chamber is tightly controlled by gating mechanisms. Dysregulation is implicated in various diseases. Components like the β-subunits serve as drug targets for cancer therapies such as bortezomib.

Other names

20S Core Particle20S CP

Inhibition of chymotrypsin-like activity