Purification of proteins with cationic surfactant

Abstract

The subject invention provides a method for purifying a target protein from a mixture comprising the target protein and contaminating protein, comprising the steps of exposing the mixture to an effective amount of a cationic surfactant such that the contaminating protein is preferentially precipitated and recovering the target protein. Proteins purified according to the method of the invention are also provided.

1 . A method for purifying a target protein comprising:
 providing a solution comprising a solubilized target protein and one or more solubilized contaminating proteins; and   contacting the solution with one or more cationic surfactants in an amount effective to selectively precipitate the one or more contaminating proteins,   thereby purifying the target protein.   
     
     
         2 . The method of  claim 1 , further comprising the step of recovering the solubilized target protein. 
     
     
         3 . The method of  claim 1  wherein at least one of the one or more cationic surfactants is an amphipathic ammonium compound. 
     
     
         4 . The method of  claim 3  wherein the amphipathic ammonium compound is selected from the group consisting of quaternary ammonium compounds of the general formula QN + ; paraffin chain primary ammonium compounds of the general formula RNH 3   + ; and salts thereof. 
     
     
         5 . The method of  claim 4  wherein the amphipathic ammonium compound is selected from the group consisting of cetylpyridinium salts, stearamide-methylpyridinium salts, lauryl pyridinium salts, cetylquinolynium salts, lauryl aminopropionic acid methyl ester salts, lauryl amino propionic acid metal salts, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine and benzethonium salts. 
     
     
         6 . The method of  claim 5  wherein the amphipathic ammonium compound is selected from hexadecylpyridinium chloride, dequalinium acetate, hexadecylpyridinium chloride, cetyltrimethylammonium chloride, mixed N-alkyl dimethyl benzylammonium chloride, cetylpyridinium chloride, N,N-dimethyl-N-[2-[2-[4-(1,1,3,3,-tetramethylbutyl)-phenoxy]ethoxy]ethyl]benzenemethanammonium chloride, alkyl-dimethylbenzyl-ammonium chloride, and dichloro-benzyldimethyl-alkylammonium chloride, tetradecyl trimethylammonium bromide, dodecyl trimethylammonium bromide, cetyltrimethylammonium bromide, lauryl dimethyl betaine stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine. 
     
     
         7 . The method of  claim 5  wherein the amphipathic ammonium compound is a cetylpyridinium salt. 
     
     
         8 . (canceled) 
     
     
         9 . The method of  claim 7 , wherein the cetylpyridinium salt is cetylpyridinium chloride. 
     
     
         10 - 11 . (canceled) 
     
     
         12 . The method of  claim 1  wherein the solution further comprises one or more cellular components from  Escherichia coli.    
     
     
         13 - 16 . (canceled) 
     
     
         17 . The method of  claim 1  wherein the target protein is a recombinant protein. 
     
     
         18 . (canceled) 
     
     
         19 . The method of  claim 17 , wherein the target protein is selected from the group consisting of an antibody, an enzyme, a uricase, an interferon-beta, a factor X inhibitor, an acid deoxyribonuclease II, an elastase, a lysozyme, a papain, a peroxidase, a pancreatic ribonuclease, a trypsinogen, a trypsin, a cytochrome c, an erabutoxin,  Staphylococcus aureus  enterotoxin C1, an interferon and a monoamine oxidase A. 
     
     
         20 . The method of  claim 1 , wherein the target protein is a uricase. 
     
     
         21 . The method of  claim 20  wherein the uricase is a mammalian uricase. 
     
     
         22 . (canceled) 
     
     
         23 . The method of  claim 17  wherein the target protein is an antibody. 
     
     
         24 . (canceled) 
     
     
         25 . The method of  claim 17  wherein the target protein is an interferon. 
     
     
         26 . (canceled) 
     
     
         27 . The method of  claim 1  wherein the one or more cationic surfactants are added to a concentration of from 0.001% to 5.0%. 
     
     
         28 . The method of  claim 27  wherein the one or more cationic surfactants are added to a concentration of from 0.01% to 0.5%. 
     
     
         29 . The method of  claim 27  wherein the one or more cationic surfactants are added to a concentration of from 0.03% to 0.2%. 
     
     
         30 - 36 . (canceled) 
     
     
         37 . The method of  claim 1 , wherein the solution is substantially free of polyanions; solid supports and aggregates of the contaminating proteins. 
     
     
         38 - 39 . (canceled) 
     
     
         40 . The method of  claim 1 , wherein the target protein has an isoelectric point greater than or equal to 7. 
     
     
         41 . A purified protein prepared according to the method of  claim 1 . 
     
     
         42 . A purified uricase prepared according to the method of  claim 1 . 
     
     
         43 - 46 . (canceled) 
     
     
         47 . A method for purifying a uricase, comprising:
 a. providing a solution comprising a solubilized target protein and one or more solubilized contaminating proteins;   b. contacting the solution with one or more cationic surfactants in an amount effective to selectively precipitate the one or more contaminating proteins; and   c. recovering the soluble uricase.   
     
     
         48 . A method of increasing the percentage of a target protein in a solution of proteins comprising the steps of
 a. obtaining a solution of a plurality of proteins, wherein the proteins in solution comprise the target protein and contaminating proteins, and the target protein comprises a first percentage by weight of the total protein in the solution;   b. contacting the solution with one or more cationic surfactants in an amount effective to selectively precipitate the contaminating proteins;   wherein the target protein in the solution of step b comprises a second percentage by weight of the total protein, and the second percentage is greater than the first percentage.   
     
     
         49 . The method of  claim 47 , wherein the uricase is recombinantly expressed in a bacterial cell. 
     
     
         50 . The method of  claim 49 , wherein the uricase is recovered from inclusion bodies produced by the bacterial cell.