. Author manuscript; available in PMC: 2017 May 5.

Published in final edited form as: Eur J Pharmacol. 2015 May 7;778:44–55. doi: 10.1016/j.ejphar.2015.04.045

Table 3.

Structural/biochemical features of human mast cell proteases

Protease	Gene	Class	Activity	Structure	Inhibition
β-Tryptases	TPSAB1 and TPSB2	Serine	Tryptic	Inactive pro-monomer or heparin-bound, active tetramer	Serpin-resistant
α-Tryptase	TPSAB1	Serine	Tryptic (weak)	Inactive pro-monomer or heparin-bound tetramer	Serpin-resistant
δ-Tryptase	TPSD1	Serine	Probably inactive	Truncated; likely monomeric	Not known
γ-Tryptase	TPSG1	Serine	Tryptic	Membrane-bound	Serpin-sensitive in soluble form; unknown in transmembrane form
Mastin	Pseudo-gene	Serine	-	-	-
Chymase	CMA1	Serine	Chymotryptic, leu-ase	Monomeric, heparin-binding	Remains active bound to α₂-macroglobulin
Cathepsin G	CTSG	Serine	Chymotryptic, tryptic, leu-ase, met-ase	Monomeric, heparin-binding	Inactivated by serpins
Cathepsin C	CTSC	Thiol/cysteine	Dipeptidyl amino-peptidase	Tetrameric	Sensitive to cystatins
Carboxy-peptidase A3	CPA3	Zn⁺⁺ metallo	Exopeptidase (aromatic, neutral)	Can complex with heparin and chymase	?