20S Proteasome - 50 µg

The proteasome is a large, multi-catalytic protease complex within the eukaryotic cell. The 26S proteasome, a 60-subunit particle, is composed of a 20S core and one or two 19S regulatory particles. The catalytic core known as the 20S proteasome (700 kDa) is composed of two sets of seven β-subunits and two sets of seven α-subunits. The β1, β2, and β5 subunits possess caspase-like, trypsin-like, and chymotrypsin-like peptidolytic activities, respectively. In eukaryotic cells, the 20S proteasome is assembled with the aid of at least five assembly chaperones. The degradation of cellular proteins by the proteasome is initiated by attachment of an ubiquitin chain to the polypeptide. The ubiquitin tag is recognized by and binds to the ‘lid’, a 19S particle, followed by disassembly of ubiquitin chains, protein unfolding and subsequent translocation into the 20S proteasome.-\n-\nProteasomal activity plays essential role in major cellular events including protein qu