A single-chain polypeptide derived from bovine Tissues consisting of 58 amino-acid residues. It is an inhibitor of Proteolytic Enzymes including Chymotrypsin; Kallikrein; Plasmin; and Trypsin. It is used in the treatment of Hemorrhage associated with raised Plasma concentrations of Plasmin. It is also used to reduce Blood loss and transfusion requirements in Patients at high Risk of major Blood loss during and following open Heart Surgery with Extracorporeal Circulation. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (Electronic version). Micromedex, Inc, Englewood, CO, 1995)