Interaction of hirudin with thrombin: Identification of a minimal binding domain of hirudin that inhibits clotting activity

Journal Article · Tue Oct 18 00:00:00 EDT 1988 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00421a027· OSTI ID:6829217

Mao, S J.T.; Yates, M T; Owen, T J; Krstenansky, J L ^[1]

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1. 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), Vol. 27:21; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ANTICOAGULANTS
CROSS-LINKING
BLOOD COAGULATION
INHIBITION
PEPTIDES
AMINO ACID SEQUENCE
THROMBIN
CONFORMATIONAL CHANGES
BIOSYNTHESIS
DICHROISM
INVERTEBRATES
IODINE 125
LIQUID COLUMN CHROMATOGRAPHY
ANIMALS
BETA DECAY RADIOISOTOPES
CHEMICAL REACTIONS
CHROMATOGRAPHY
COAGULANTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HEMATOLOGIC AGENTS
HEMOSTATICS
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
POLYMERIZATION
PROTEINS
RADIOISOTOPES
SEPARATION PROCESSES
SERINE PROTEINASES
SYNTHESIS
550201* - Biochemistry- Tracer Techniques