Protein Z-dependent protease inhibitor

Abstract

The disclosure describes the purification and isolation of a novel human protein Z-dependent protease inhibitor (ZPI) from plasma characterized as having a molecular weight of about 72 kDa, being a single chain protein with an N-terminal amino acid sequence of LAPSPQSPETPA, and which produces a rapid inhibition of factor Xa in the presence of human protein Z (PZ), calcium ions and cephalin. The disclosure further describes the isolation and cloning of the ZPI cDNA from a human cDNA library. The ZPI cDNA is 2.44 kb in length and has an open reading frame that encodes the 423 residue mature ZPI protein and a 21 residue signal peptide. PZ, ZPI and the combination of PZ and ZPI are used to inhibit blood coagulation.

What is claimed is:  
     
         1 . A purified and isolated human protein Z-dependent protease inhibitor characterized as: 
 (a) having a molecular weight of about 72 kDa,    (b) being a single chain protein with an N-terminal amino acid sequence of Leu Ala Pro Ser Pro Gln Ser Pro Glu Thr 1 5 10 Pro Ala [SEQ ID NO:16], and    (c) producing rapid inhibition of factor Xa in the presence of protein Z, calcium ions and cephalin.    
     
     
         2 . A method of inhibiting factor Xa in serum or plasma comprising contacting said serum or plasma with an effective inhibitory amount of the human Protein Z-dependent protease inhibitor of  claim 1 .  
     
     
         3 . A purified and isolated DNA molecule comprising a nucleotide sequence encoding the 423 amino acid sequence of SEQ ID NO: 8.  
     
     
         4 . A purified and isolated DNA molecule of  claim 3  having the nucleotide sequence of SEQ ID NO: 7.  
     
     
         5 . A purified and isolated protein Z-dependent protease inhibitor having the 423 amino acid sequence of SEQ ID NO: 8.  
     
     
         6 . A method of inhibiting factor Xa in serum or plasma comprising contacting said serum or plasma with an effective inhibitory amount of the human protein Z-dependent protease inhibitor of  claim 5 .  
     
     
         7 . A method of inhibiting blood coagulation in a patient in need thereof comprising administering to said patient a coagulation inhibitor selected from the group consisting of protein Z, ZPI and a combination of protein Z and ZPI in an amount sufficient to inhibit blood coagulation.  
     
     
         8 . The method of  claim 7  in which the coagulation inhibitor is protein Z.  
     
     
         9 . The method of  claim 7  in which the coagulation inhibitor is ZPI.  
     
     
         10 . The method of  claim 9  in which the ZPI has the 423 amino acid sequence of SEQ ID NO:8.  
     
     
         11 . The method of  claim 7  in which the coagulation inhibitor is a combination of protein Z and ZPI.  
     
     
         12 . The method of  claim 11  in which the ZPI has the 423 amino acid sequence of SEQ ID NO:8.  
     
     
         13 . A pharmaceutical composition comprising protein Z and ZPI in a pharmaceutically acceptable carrier or diluent.  
     
     
         14 . The composition of  claim 13  in which the ZPI has the 423 amino acid sequence of SEQ ID NO:8.