Tryptase (TPS)

Tryptase is the most abundant secretory granule-derived serine proteinase contained in mast cells that has recently been used as a marker for mast cell activation. It is involved with allergenic response and is suspected to act as a mitogen for fibroblast lines. Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude anaphylaxis.

Tryptases comprise a family of trypsin-like serine proteases, the peptidase family S1. Tryptases are enzymatically active only as heparin-stabilized tetramers, and they are resistant to all known endogenous proteinase inhibitors. Several tryptase genes are clustered on chromosome 16p13.3. These genes are characterized by several distinct features.