20S Proteasome
20s proteasome
"The 20S proteasome, as proteolytic core of the proteasome system, is essential in ATP dependent ubiquitin protein complex degradation and in antigen processing in antigen presenting cell. It has 13-15 subunits each of which has three or four different peptidase activities. 26S proteasomes may be formed in an ATP dependent fashion from a 20S proteasome and additional components, CF1 (660 kD), CF2 (250 kD) and CF3 (600 kD). The 20S proteasome interacts with additional subunits, PA700 and PA28, to form an ATP-dependent multicatalytic proteinase complex (MPC) involved in the ATP ubiquitin degradation pathway."