Abundant protease in the cytosolic granules of cytotoxic T-cells and NK-cells which activates caspase-independent pyroptosis when delivered into the target cell through the immunological synapse (PubMed:3257574, PubMed:3262682, PubMed:3263427, PubMed:32299851, PubMed:12819770). It cleaves after Lys or Arg (PubMed:32299851, PubMed:12819770). Once delivered into the target cell, acts by catalyzing cleavage of gasdermin-B (GSDMB), releasing the pore-forming moiety of GSDMB, thereby triggering pyroptosis and target cell death (PubMed:32299851). Cleaves APEX1 after 'Lys-31' and destroys its oxidative repair activity (PubMed:12524539). Cleaves the nucleosome assembly protein SET after 'Lys-189', which disrupts its nucleosome assembly activity and allows the SET complex to translocate into the nucleus to nick and degrade the DNA (PubMed:11555662, PubMed:12628186, PubMed:16818237). Hydrolysis of proteins, including fibronectin, type IV collagen and nucleolin. Preferential cleavage: -Arg-|-Xaa-, -Lys-|-Xaa- >> -Phe-|-Xaa- in small molecule substrates. Homodimer; disulfide-linked (PubMed:12819769, PubMed:12819770). Interacts with APEX1 (PubMed:12524539). Delivered into the target cell by perforin. Dexamethasone (DEX) induces expression of isoform beta and represses expression of isoform alpha. The alteration in expression is mediated by binding of glucocorticoid receptor to independent promoters adjacent to the alternative first exons of isoform alpha and isoform beta. Belongs to the peptidase S1 family. Granzyme subfamily. Exons 1a and 1b of the sequence reported in PubMed:17180578 are of human origin, however exon 2 shows strong similarity to the rat sequence.