Tryptase beta-2(Tpsb2), also known as Mast cell protease 6(mMCP-6), belongs to the peptidase S1 family and Tryptase subfamily. Tryptase is the major neutral protease present in mast cells and is secreted upon the coupled activation-degranulation response of this cell type. It plays a role in innate immunity. Tpsb2 can be detected primarily in skin during embryogenesis. Tpsb2 can not be detected at early embryonic stages but is abundantly expressed in later stages with a peak at E17.5-E18.5. Tryptase is a homotetramer. The active tetramer is converted to inactive monomers at neutral and acidic pH in the absence of heparin. Low concentrations of inactive monomers become active monomers at pH 6.0 in the presence of heparin. When the concentration of active monomers is higher, they convert to active monomers and then to active tetramers. These monomers are active and functionally distinct from the tetrameric enzyme. In contrast to the hidden active sites in the tetrameric form, the active site of the monomeric form is accessible for macromolecular proteins and inhibitors eg: fibrinogen which is a substrate for the monomeric but not for the tetrameric form. The monomeric form forms a complex with SERPINB6.