X is an alias for the gene, Proteasome subunit beta 5, in humans. Other names include: Proteasome subunit beta type-5; Multicatalytic endopeptidase complex epsilon chain; Proteasome chain 6; Proteasome epsilon chain; Proteasome subunit MB1; Proteasome subunit X; Macropain epsilon chain; Proteasome subunit beta type-5 ; LMPX; MB1; proteasome (prosome, macropain) subunit, beta type, 5. The encoded protein is an enzyme with an amino acid length of 263 and a mass of 28.5 kDa. X is a member of the Peptidase T1B family. This gene shares homology with other species, including: Mouse, Fly, Rat, Zebrafish, Frog, Chicken.