PSMB11 belongs to the peptidase T1B family. It is a multicatalytic proteinase complex which is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. PSMB11 has an ATP-dependent proteolytic activity. Incorporated instead of PSMB5 or PSMB8, this unit reduces the chymotrypsin-like activity of the proteasome. It plays a pivotal role in development of CD8-positive T cells. The antibody is specific to PSMB11.