Interaction of hirudin with thrombin: Identification of a minimal binding domain of hirudin that inhibits clotting activity
- Merrell Dow Research Institute, Cincinnati, OH (USA)
Hirudin, isolated from the European leech Hirudo medicinalis, is a potent inhibitor of thrombin, forming an almost irreversible thrombin-hirudin complex. Previously, the authors have shown that the carboxyl terminus of hirudin (residues 45-65) inhibits clotting activity and without binding to the catalytic site of thrombin. In the present study, a series of peptides corresponding to this carboxyl-terminal region of hirudin have been synthesized, and their anticoagulant activity and binding properties to thrombin were examined. Binding was assessed by their ability to displace {sup 125}I-hirudin 45-65 from Sepharose-immobilized thrombin and by isolation of peptide-thrombin complexes. They show that the carboxyl-terminal 10 amino acid residues 56-65 (Phe-Glu-Glu-Ile-Pro-Glu-Glu-Tyr-Leu-Gln) are minimally required for binding to thrombin and inhibition of clotting. Phe-56 was critical for maintaining anticoagulant activity as demonstrated by the loss of activity when Phe-56 was substituted with D-Phe, Glu, or Leu. In addition, they found that the binding of the carboxyl-terminal peptide of hirudin with thrombin was associated with a significant conformational change of thrombin as judged by circular dichroism. This conformational change might be responsible for the loss of clotting activity of thrombin.
- OSTI ID:
- 6829217
- Journal Information:
- Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 27:21; ISSN 0006-2960; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Equilibrium binding of thrombin to recombinant human thrombomodulin: Effect of hirudin, fibrinogen, factor Va, and peptide analogues
High-resolution NMR studies of fibrinogen-like peptides in solution: Interaction of thrombin with residues 1-23 of the A. alpha. chain of human fibrinogen
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
ANIMALS
ANTICOAGULANTS
BETA DECAY RADIOISOTOPES
BIOSYNTHESIS
BLOOD COAGULATION
CHEMICAL REACTIONS
CHROMATOGRAPHY
COAGULANTS
CONFORMATIONAL CHANGES
CROSS-LINKING
DAYS LIVING RADIOISOTOPES
DICHROISM
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
INHIBITION
INTERMEDIATE MASS NUCLEI
INVERTEBRATES
IODINE 125
IODINE ISOTOPES
ISOTOPES
LIQUID COLUMN CHROMATOGRAPHY
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PEPTIDES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
SEPARATION PROCESSES
SERINE PROTEINASES
SYNTHESIS
THROMBIN