von Willebrand Factor (vWF) - Cleaving Protease

Abstract

This invention is intended to isolate and identify a vWF-specific cleaving protease. The vWF-specific cleaving protease cleaves a bond between residues Tyr 842 and Met 843 of vWF and comprises a polypeptide chain having Leu-Leu-Val-Ala-Val (SEQ ID NO: 1) as a partial sequence, and more preferably comprises a polypeptide chain having the partial N-terminal amino acid sequence of a mature protein, Ala-Ala-Gly-Gly-Ile-Leu-His-Leu-Glu-Leu-Leu-Val-Ala-Val (SEQ ID NO: 2), and having a molecular weight of 105 to 160 kDa in SDS-PAGE under reducing or non-reducing conditions. Isolation and identification of this vWF-specific cleaving protease have led to the possibility of replacement therapy for patients having diseases resulting from a deficiency of the protease, such as thrombotic thrombocytopenic purpura.

1 . An antibody against a protease comprising a polypeptide chain having the amino acid sequence Leu-Leu-Val-Ala-Val, wherein the protease is capable of cleaving a bond between residues Tyr-842 and Met-843 of von Willebrand factor. 
     
     
         2 . The antibody according to  claim 1 , wherein the antibody inhibits or neutralizes the activity of a von Willebrand factor cleaving protease. 
     
     
         3 . A pharmaceutical composition or diagnostic agent comprising an antibody against an isolated protease comprising a polypeptide chain having the amino acid sequence Leu-Leu-Val-Ala-Val (SEQ ID NO: 1), wherein the protease is capable of cleaving a bond between residues Tyr-842 and Met-843 of von Willebrand factor.