Serine endopeptidase which hydrolyzes a range of fluorogenic peptide substrates containing the basic residues arginine or lysine at the P1 position and prefers paired basic resides. Also hydrolyzes clupeine and salmine, activates plasminogen and converts trypsinogen to trypsin. Binds 1 Ca(2+) ion per subunit. Inhibited by antipain and leupeptin. The highest catalytic efficiency is observed for Boc-Leu-Lys-Arg-MCA. Optimum pH is 4.0. Inactive below pH 3.0 and above pH 6.5. The half-life (t1/2) values for activity loss at 30 degrees Celsius are 150 min at pH 6.6, 5.5 min at pH 6.8 and 14 min at pH 2.4. Remains fully active after heating at 50 degrees Celsius and pH 4.0 for 10 min. Retains 65% of its activity after heating at 55 degrees Celsius for 10 min. The half-life value for loss of activity at 60 degrees Celsius and pH 4.0 is 3.5 min. Activity found in solid culture only. Increases at the initial growth stage and decreases in the late growth stage. N-glycosylated. O-glycosylated.