This highly disulfide-bonded protein is a potent inhibitor of factor Xa. Facilitates digestion of tissues and may also protect the gastric tissues from its own digestive enzymes. May have therapeutic utility as an anticoagulant. Also exhibits a strong metastatic activity. Gland cells. It is more strongly expressed in the head than in the gastric tissue. Belongs to the protease inhibitor I15 (antistasin) family.