The Ubiquitin Proteasome Pathway (UPP) is the cell’s principle mechanism for protein catabolism. The UPP has been shown to have significant involvement in the regulation of critical cellular processes such as transcription, oncogenesis, cell cycle progression, development, growth, selective elimination of abnormal proteins, and antigen processing (Glickman, 2002)).The proteasome is a large, multimeric protease that catalyzes the final step of the UPP intracellular protein degradation. The proteasome exists in multiple forms within the eukaryotic cell, and contained in all isoforms is the catalytic core known as the 20S proteasome. The 20S proteasome (700 kDa) is arranged as four axially stacked heptameric rings with two β-subunit rings sandwiched between two α-subunit rings. The multicatalytic centers are located within the internal cavity of the β-subunits. The 26S Proteasome is defined by having one or two19S regulatory caps on the 20S core particle. It is the 26S that is responsible for the recognition and subsequent degradation of poly-ubiquitinated proteins into smaller polypeptides. This degradation is ubiquitin and ATP dependent and will not be 26S proteasome mediated unless target substrate is first ubiquitinated via the conjugation cascade.