Bovine pancreatic trypsin inhibitor (BPTI) (BPTI)

Bovine pancreatic trypsin inhibitor (BPTI), clinically known as aprotinin, is a small 58-amino acid polypeptide and a member of the Kunitz-type serine protease inhibitor family (UniProt P00974). Primarily isolated from bovine lung and pancreatic tissues, it acts as a potent broad-spectrum inhibitor of multiple serine proteases, including trypsin, plasmin, and kallikrein (PubChem CID 16130295). Its primary therapeutic application is as an antifibrinolytic agent, used to minimize perioperative blood loss and reduce the need for blood transfusions in patients undergoing high-risk procedures such as cardiac surgery or liver transplantation (Wikipedia; AHFS). BPTI works by reversibly binding to the active site of these enzymes, thereby preventing the degradation of fibrin clots and dampening the systemic inflammatory response (PubMed PMID 11789829). In addition to its hemostatic roles, research has explored its potential as an antiviral agent due to its ability to inhibit host cell proteases required for viral activation, such as those used by influenza and SARS-CoV-2 (PMC8870125). Despite its clinical benefits in hemostasis, BPTI has been associated with significant safety risks, including renal toxicity and severe hypersensitivity reactions, which have led to restricted indications and rigorous monitoring (PubMed PMID 17898372). This molecule also serves as a foundational model for protein folding and structural biology studies due to its stability and well-characterized three-dimensional structure (Ascenzi et al., 2003).

Other names

AprotininBasic protease inhibitorTrypsin-kallikrein inhibitorBPITrasylolKunitz inhibitor

Bovine pancreatic trypsin inhibitor (BPTI) is a pharmacological agent (aprotinin) rather than a therapeutic target. As a drug, it acts as a competitive and reversible inhibitor of various serine proteases, specifically trypsin, chymotrypsin, plasmin, and kallikrein. Its mechanism involves forming stable complexes with the active sites of these enzymes, thereby preventing substrate cleavage and slowing down processes such as fibrinolysis and the systemic inflammatory response (PubMed PMID 11789829).