TPSAB1, also known as tryptase alpha/beta-1, is a serine protease with trypsin-like specificity. It is the key neutral protease present in mast cells and is discharged upon the coupled activation-degranulation response of this cell type. This protein is enzymatically active only as a heparin-stabilized tetramer, and is resistant to all known endogenous proteinase inhibitors. Also, it is implicated as a mediator in the pathogenesis of asthma and other allergic and inflammatory disorders. Recombinant human TPSAB1, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.