Human beta-tryptase (β-tryptase)

Human beta-tryptase is a trypsin-like serine protease and the predominant secretory granule protease of human mast cells[3][5]. Unlike most serine proteases, **active human beta-tryptase exists as a noncovalent tetramer** stabilized by heparin proteoglycans, with all active sites facing inward toward a central pore, a configuration that restricts access to large-molecule inhibitors and natural protein substrates[2][3][5]. It plays a *critical role* in immune responses, especially in allergic conditions such as asthma and anaphylaxis, through the proteolytic activation of substrates including protease-activated receptor 2 (PAR-2)[3][7]. Genes encoding beta-tryptase include TPSB2 and TPSAB1 on human chromosome 16p13.3, and the protein is distinguished from closely related alpha and gamma tryptases by small sequence and functional differences[2][7]. **Elevated serum tryptase** is a key biomarker for mast cell activation and is clinically significant in the diagnosis of anaphylaxis and mastocytosis[9]. Beta-tryptase’s structure and resistance to endogenous protease inhibitors make it an *attractive but challenging therapeutic target* in diseases involving mast cell-mediated inflammation, and several small molecule and bivalent inhibitors are in experimental stages, though no selective inhibitors are yet clinically approved[4][5][7].

Other names

Mast cell tryptasetryptase betamast cell protease IIskin tryptaselung tryptasemast cell serine protease IImast cell proteinase IIbeta-tryptase

Serine protease inhibition, Active site binding (often allosterically or via bivalent occupancy of the central pore), Inhibition of tetramer stabilization (heparin-mimetic), Blockade of substrate access to the active site