Bovine pancreatic trypsin inhibitor, or BPTI, is a protein found in many tissues throughout the body. BPTI inhibits several of the serine protease proteins such as trypsin, kallikrein, chymotrypsin, and plasmin. BPTI is a member of the pancreatic trypsin inhibitor (kunitz) family, which is a family of serine protease inhibitors. These proteins usually have conserved cysteine residues that participate in forming disulfide bonds. Shown here in blue are the three disulfide bonds in BPTI. They are as follows: Cys5-Cys55, Cys14-Cys38, and Cys30-Cys51.
BPTI is a monomeric polypeptide containing 58 amino acid residues. The picture shown here is colored by secondary structure. All beta sheets are colored hot pink. The two alpha helices are colored differently: Green= a right-handed alpha helix, gold= a 310 alpha helix. 

• Keywords: Serine Protease Inhibitor
• View this protein's PDB entry as 1PIT
• View this protein's SwissProt entry as BPTI_BOVIN
• References:
• K.D. Berndt, P. Guntert, L.P.M. Orbons, K. Wuthrich

Determination of a High-Quality Nuclear Magnetic Resonance Solution Structure of the Bovine Pancreatic Trypsin Inhibitor and Comparison With Three Crystal Structures.
J. Mol. Biol. 227:757 (1992)
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• G. Wagner, W. Braun, T.F. Havel, T. Schaumann, N. Go, K. Wuthrich

Protein Structures in Solution by Nuclear Magnetic Resonance and Distance Geometry: The Polypeptide Fold of the Basic Pancreatic Trypsin Inhibitor Determined Using Two Different Algorithms, DISGEO and DISMAN.
J. Mol. Biol. 196:611 (1987)
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• G. Wagner, K. Wuthrich

Sequential Resonance Assignments in Protein 1H Nuclear Magnetic Resonance Spectra. Basic Pancreatic Trypsin Inhibitor.
J. Mol. Biol. 155:347 (1982)
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