20S Proteasome

**Semantic type:** Amino Acid, Peptide, or Protein|Cell Component

**Definition:** 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.

**Synonyms:** - 20S Catalytic Proteasome - 20S Core Proteasome - 20S Proteosome