Has kallikrein-like activity, converts kininogens to kinins, and has dilatory effects on the blood vessel walls. Shows highest activity toward Pro-Phe-Arg-MCA and Boc-Val-Leu-Lys-MCA in vitro. Has preference for Arg and Lys in position P1 and hydrophobic residues in position P2. Strongly inhibited by aprotinin, moderately inhibited by secretory leukoprotease inhibitor, the Kunitz-type soybean trypsin inhibitor, and leupeptin, and not inhibited by urinary trypsin inhibitor or alpha-1 protease inhibitor. Optimum pH is 9.0. Submaxillary and sublingual salivary glands. LD(50) is 1 mg/kg by intraperitoneal injection into mice. This injection causes irregular respiration, paralysis, convulsions and death. Belongs to the peptidase S1 family. Kallikrein subfamily.