Definition:

Type II transmembrane serine proteases (TTSPs) are an N-terminal transmembrane domain, a C-terminal extracellular serine protease domain of the chymotrypsin (S1) fold that contains the catalytic histidine, aspartic acid, and serine residues, and a “stem region” that may contain an assortment of 1-11 protein domains of six different types. Type II transmembrane serine proteases (TTSPs) could function as initiators of proteolytic cascades.