Endopeptidase activities associated with the plasma membrane compartment of an antigen-presenting B cell

Endopeptidase activity was characterized in plasma membranes prepared from an antigen-presenting B cell lymphoma, A20. Activity was detected at both neutral and acid pH, and studies with inhibitors confirmed that a number of different enzymes, most probably cysteine, metallo, and aspartic endopeptidases, were associated with the A20 cell surface.