Development of MDL 28,050, a Small Stable Antithrombin Agent Based on a Functional Domain of the Leech Protein, Hirudin

Summary

MDL 28,050 is a decapeptide antithrombin agent that inhibits a-thrombin-induced fibrin clot formation by binding to a non-catalytic site on α-thromhin. It is the result of chemical and structural optimization of a functional domain of the leech anticoagulant, hirudin. In contrast to the contention that the polyanionic nature of this C-terminal functional domain governs its interaction with α-thrombin, systematic study of this region has shown the importance of the lipophilic residues for providing the functionality necessary foi potent binding to a-thrombin. The development of MDL 28,050 and other effective antithrombin agents are outlined through the description of the structure-activity relationships (SAR) for these peptides. These peptides are effective in a variety of in vitro and in vivo models of thrombosis.

• References

• 1 Markwardt M. Hirudin as an inhibitor of thrombin. Methods Enzymol 1970; 19: 924-932
• 2 Tertrin C, de la Llosa P, Jutisz M. Effet des modifications chimiques de Fhirudine sur son action inhibitrice de l’activité enzymatique de la thrombine. Bull Soc Chim Biol 1967; 49: 1837-1843
• 3 Bagdy D, Barabas E, Graf L, Ellebaek T, Magnusson SHirudin. Methods Enzymol 1976; 45: 669-678
• 4 Dodt J, Muller HP, Seemuller U, Chang JY. The complete amino acid sequence of hirudin, a thrombin specific inhibitor. FEBS Lett 1984; 165: 180-184
• 5 Dodt J, Seemuller U, Maschler R, Fritz H. The complete covalent structure of hirudin. Biol Chem Hoppe-Seyler 1985; 366: 379-385
• 6 Chang JY. The functional domain of hirudin, a thrombin-specific inhibitor. FEBS Lett 1983; 164: 307-313
• 7 Bajusz S, Fauszt I, Barabas E, Dioszegi M, Bagdy D. Thrombin inhibition by hirudin fragments: Possible mechanism of hirudin-thrombin interaction. In: Peptides 1984 Pagnarsson U. ed Alinqvisl & Wiksell Inti; Stockholm: 1984. pp 473-476
• 8 Fenton II JW, Olson TA, Zabrinski MP, Wilner GD. Anion-binding cxositc of human u-lliiombin and fibrin(ogen) recognition. Biochemistry 1988; 27: 7106-7112
• 9 Krstenansky JL, Mao SJ T. Antithrombin properties of C-tcrminus of hirudin using synthetic unsulfated N^α-acetyl-hirudin_54–65 . FEBS Lett 1987; 211: 10-16
• 10 Mao SJ T, Yates MT, Owen TJ, Krstenansky JL. Interaction of hirudin with thrombin: Identification of a minimal binding domain that inhibits clotting activity. Biochemistry 1988; 27: 8170-8173
• 11 Krstenansky JL, Owen TJ, Yates MT, Mao SJ T. Anticoagulant peptides: Nature of the interaction of the C-temiinal region of hirudin with a non-catalytic binding site on thrombin. J Med Chcm 1987; 30: 1688-1691
• 12 Owen TJ, Krstenansky JL, Yates MT, Mao SJ T. N-tenninal requirements of small peptide anticoagulants based on hirudin_54–65 . J Med Chem 1988; 31: 1009-1011
• 13 Krstenansky JL, Owen TJ, Yates MT, Mao SJ T. Comparison of hirudin and hirudin PA C-terminal fragments and related analogs as antithrombin agents. Thromb Res 1988; 52: 137-141
• 14 Stewart JM, Young JD. Preparation of Boc amino acids. In: Solid Phase Peptide Synthesis Second Edition Pierce Chemical Co; Rockford: 1984. pp 61-64
• 15 Dodt J, Machleidt W, Seemuller U, Maschler W, Fritz H. Isolation and characterization of hirudin isoinhibitors and sequence analysis of hirudin PA. Biol Chem Hoppe-Seyler 1986; 367: 803-811
• 16 Krstenansky JL, Owen TJ, Yates MT, Mao SJ T. Design, synthesis and antithrombin activity for conformationally restricted analogs of peptide anticoagulants based on the C-terminal region of the leech peptide, hirudin. Biochim Biophys Acta 1988; 957: 53-59
• 17 Krstenansky JL, Owen TJ, Payne MH, Broersma RJ, Yates MT, Mao SJ T. MDL 28,050, Representative of a new class of anticoagulant. In: Peptides: Chemistry and Biology Proceedings of the Eleventh American Peptide Symposium. Rivier J. (ed) Escom; Leiden: 1989. in press