Tryptase (, ) is the most abundant secretory granule-derived serine proteinase contained in

mast cell A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the myeloid stem cell that is a par ...

s and has been used as a marker for mast cell activation. Club cells contain tryptase, which is believed to be responsible for cleaving the

hemagglutinin In molecular biology, hemagglutinins (or ''haemagglutinin'' in British English) (from the Greek , 'blood' + Latin , 'glue') are receptor-binding membrane fusion glycoproteins produced by viruses in the '' Paramyxoviridae'' family. Hemagglutinins a ...

surface protein of influenza A virus, thereby activating it and causing the symptoms of flu.

Nomenclature

Tryptase is also known by mast cell tryptase, mast cell protease II, skin tryptase, lung tryptase, pituitary tryptase, mast cell neutral proteinase, mast cell serine proteinase II, mast cell proteinase II, mast cell serine proteinase tryptase, rat mast cell protease II, and tryptase M.

Clinical use

Serum levels are normally less than 11.5 ng/mL. Elevated levels of serum tryptase occur in both anaphylactic and anaphylactoid reactions, but a negative test does not exclude

anaphylaxis Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the follo ...

. Tryptase is less likely to be elevated in food allergy reactions as opposed to other causes of anaphylaxis. Serum tryptase levels are also elevated in and used as one indication suggesting the presence of

eosinophilic leukemia Types of eosinophilic leukemia include: * Chronic eosinophilic leukemia * Acute eosinophilic leukemia * Clonal eosinophilia Clonal hypereosinophilia, also termed primary hypereosinophilia or clonal eosinophilia, is a grouping of hematological disor ...

s due to genetic mutations resulting in the formation of ''FIP1L1-PDGFRA'' fusion genes or the presence of systemic mastocytosis.

Physiology

Tryptase is involved with allergenic response and is suspected to act as a mitogen for

fibroblast A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells ...

lines. Tryptase may use the

morpheein Morpheeins are proteins that can form two or more different homo-oligomers (morpheein forms), but must come apart and change shape to convert between forms. The alternate shape may reassemble to a different oligomer. The shape of the subunit ...

model of

allosteric regulation In biochemistry, allosteric regulation (or allosteric control) is the regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site. The site to which the effector binds is termed the ''allosteric sit ...

. Mast cell tryptase-6 is involved in

Trichinella spiralis ''Trichinella spiralis'' is a viviparous nematode parasite, occurring in rodents, pigs, bears, hyenas and humans, and is responsible for the disease trichinosis. It is sometimes referred to as the "pork worm" due to it being typically encount ...

infection in mice through linking adaptive and

innate immunity The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...

Genes

Human genes that encode proteins with tryptase activity include: Mouse genes that encode proteins with tryptase activity include:

References

External links

* EC 3.4.21 {{hydrolase-stub