The proteasome (protein complexes which degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds) is a multicatalytic proteinase complex with a highly ordered 20S core structure is composed of four axially stacked rings of 28 non-identical subunits: the two end rings are each formed by seven alpha subunits, and the two central rings are each formed by seven beta subunits.
Proteasomes are protein complexes which degrade unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. The proteasome is a multicatalytic proteinase complex with a highly ordered 20S core structure. This barrel-shaped core structure is composed of 4 axially stacked rings of 28 non-identical subunits: the two end rings are each formed by 7 alpha subunits, and the two central rings are each formed by 7 beta subunits. 
