leukocyte granule-associated proteinase PR:000003505 A trypsin that is a serine protease of the granules from mast cells, cytotoxic T lymphocytes and/or natural killer cells. Leukocyte granule-associated proteinase is a component of the immune system that protect higher organisms against viral infection and cellular transformation. Members of this class have features that are strongly conserved including: consensus sequences at their N-termini and around the three catalytic residues, activation from zymogenic forms, and conserved disulphide bridges. Category=family. protein trypsin