Possesses a trypsin-like cleavage specificity with a preference for poly-basic substrates. Stimulates epithelial sodium channel (ENaC) activity through activating cleavage of the gamma subunits (SCNN1G). Heterodimer of two chains, light and heavy, held by a disulfide bond. Found in the seminal fluid. Secreted after cleavage of its C-terminus. Found in the seminal fluid. Secreted after cleavage of its C-terminus. Found in prostate, liver, salivary gland, kidney, lung, pancreas, colon, bronchus and renal proximal tubular cells. In the prostate gland it may be synthesized in epithelial cells, secreted into the ducts, and excreted into the seminal fluid. Belongs to the peptidase S1 family.