proteasome

noun

pro·​te·​a·​some ˈprō-tē-ə-ˌsōm 

: a hollow, cylindrical cellular structure that is a complex of proteases involved in the selective degradation of intracellular proteins and especially proteins marked for proteolysis by ubiquitin

Tagged proteins are then fed into the proteasome, a barrel-shaped multi-protein complex that chops proteins down into their component amino acids for reuse.

—Caroline Williams, New Scientist