Granzyme B(GZMB) contains 1 peptidase S1 domain and belongs to the peptidase S1 family. This enzyme is necessary for target cell lysis in cell-mediated immune responses. It cleaves after Asp and seems to be linked to an activation cascade of caspases (aspartate-specific cysteine proteases) responsible for apoptosis execution. The protein cleaves caspase-3, -7, -9 and 10 to give rise to active enzymes mediating apoptosis.