Antithrombosis enzyme from the snake venom of Agkistrodon acutus

Abstract

This invention features an antithrombosis enzyme extracted and purified from the snake venom of Southern-Anhui Agkistrodon acutus and pharmaceutical uses thereof.

1 . An isolated, purified or recombinant antithrombosis enzyme having the following characteristics: 
 the molecular weight of said enzyme is between about 28 kD and about 32 kD when analyzed by polyacrylamide gel electrophoresis,    the aspartic acid content of said enzyme is between about 2% and about 5%,    the glutamic acid content of said enzyme is between about 2% and about 5%, and    said enzyme hydrolyzes fibrin, dissolves blood clots, and prevents platelet aggregation.    
     
     
         2 . The enzyme of  claim 1  which hydrolyzes fibrin at a level of no less than one fibrinolytic activity unit per mg of said enzyme.  
     
     
         3 . The enzyme of  claim 1  which hydrolyzes fibrin at a level of about one to about three fibrinolytic activity units per mg of said enzyme.  
     
     
         4 . The enzyme of  claim 1  which is isolated or purified from the venom of Southern-Anhui  Agkistrodon acutus.    
     
     
         5 . The enzyme of  claim 1  which inhibits human platelet aggregation induced by a fibrin agonist selected from the group consisting of ADP, epinephrine and thrombin.  
     
     
         6 . The enzyme of  claim 1 , wherein said enzyme has nondetectable level of casein hydrolysis activity.  
     
     
         7 . The enzyme of  claim 1 , wherein said enzyme comprises Ca ++ .  
     
     
         8 . The enzyme of  claim 1 , wherein the amino terminus of said enzyme is aspartic acid.  
     
     
         9 . The enzyme of  claim 1  comprising two polypeptide chains of about 14 kD to about 16 kD when analyzed by polyacrylamide gel electrophoresis.  
     
     
         10 . The enzyme of  claim 9  wherein one of said two polypeptide chains comprises an amino acid sequence, from left to right in the direction from the amino terminus to the carboxy terminus, represented by the formula:  
       
         
           
                 
                 
               
                     
                 
                   Asp-Cys-Ser-Ser-Asp-Trp-Ser-Ser-Tyr-Glu-Gly-His- 
                     
                 
                     
                 
                   Cys-Tyr-Lys-Val-Phe-Lys-Gln-Ser-Lys-Thr-Trp-Thr- 
                 
                     
                 
                   Asp-Ala-Glu-Ser-Phe-. 
                 
                     
                 
             
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         11 . The enzyme of  claim 9  wherein one of said two polypeptide chains comprises an amino acid sequence, from left to right in the direction from the amino terminus to the carboxy terminus, represented by the formula:  
       
         
           
                 
                 
               
                     
                 
                   Asp-Cys-Pro-Ser-Glu-Trp-Ser-Ser-Tyr-Glu-Gly-Phe- 
                     
                 
                     
                 
                   Cys-Tyr-Lys-Pro-Phe-. 
                 
                     
                 
             
                
                
                
                
                
               
            
           
         
       
     
     
         12 . The enzyme of  claim 9  wherein one of said two polypeptide chains comprises an amino acid sequence of SEQ ID NO: 2.  
     
     
         13 . The enzyme of  claim 1  which is crystallized.  
     
     
         14 . An isolated, purified or recombinant polypeptide comprising no less than 20 contiguous amino acids from SEQ ID NO: 2.  
     
     
         15 . An isolated, purified or enriched recombinant nucleic acid comprising no less than 60 contiguous nucleotides from SEQ ID NO: 1 or its fully complementary strand of the same length and a promoter effective to initiate transcription of said contiguous nucleotides in a host cell.  
     
     
         16 . An isolated, purified, or recombinant polypeptide comprising SEQ ID NO: 2.  
     
     
         17 . An isolated, purified or enriched recombinant nucleic acid comprising a contiguous nucleic acid sequence encoding SEQ ID NO: 2 and a promoter effective to initiate transcription of said contiguous nucleic acid sequence in a host cell.  
     
     
         18 . An isolated, purified or enriched recombinant nucleic acid comprising SEQ ID NO: 1 or its fully complementary strand of the same length and a promoter effective to initiate transcription of said contiguous nucleotides in a host cell.  
     
     
         19 . A pharmaceutical composition comprising a pharmaceutically effective amount of an enzyme of  claim 1  and a pharmaceutically acceptable carrier.  
     
     
         20 . A method for dissolving a thrombus in a mammal, comprising the step of administering to said mammal a pharmaceutically effective amount of an enzyme of  claim 1 .  
     
     
         21 . A method for treating or preventing a thrombosis related disease in a mammal, comprising the step of administering to said mammal a pharmaceutically effective amount of an enzyme of  claim 1 .  
     
     
         22 . The method of  claim 21 , wherein said thrombosis related disease is selected from the group consisting of myocardial infarction, restenosis, unstable angina and cerebral thrombosis.