Mast cell protease synthesis

Histamine is synthesized from the amino acid histidine by an action of the enzyme histidine decarboxylase (Fig. 38.1). Following synthesis, histamine is either rapidly inactivated or stored in the secretory granules of mast cells and basophils as an inactive complex with proteases and heparin sulfate or chondroitin sulfate. 

In addition to the use in the synthesis of potential hepatitis C drugs, microwave-assisted chemistry has also been used in the synthesis of mast cell tryptase inhibitors, thrombin inhibitors, and Factor Xa inhibitors. The trypsin-like serine protease tryptase is the major secretory product of human mast cells and has been implicated as an inflammatory mediator in a number of conditions, especially asthma. Once released upon mast cell activation, the tryptase cleaves substrates that otherwise cause smooth muscle relaxation and thereby bronchi- and vasodilation. It is therefore not surprising that numerous reports on low molecular weight tryptase inhibitors have appeared. 

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