Separation of polypeptide monomers

Abstract

A method is disclosed for separating a polypeptide monomer from a mixture comprising dimers and/or multimers. The method comprises applying the mixture to either a cation-exchange chromatography resin or an anion-exchange chromatography resin and eluting the mixture at a gradient of about 0-1 M of an elution salt, wherein the monomer is separated from the dimers and/or multimers present in the mixture.

What is claimed is:  
     
         1 . A method for purifying polypeptide monomers from a mixture consisting essentially of said polypeptide monomers, and dimers or multimers of said polypeptide monomers or both dimers and multimers of said polypeptide monomers, wherein the method comprises: 
 (a) applying the mixture to a cation-exchange or anion-exchange chromatography resin in a buffer, wherein if the resin is cation-exchange, the pH of the buffer is about 4-7, and wherein if the resin is anion-exchange, the pH of the buffer is about 6-9,    (b) eluting the mixture at a gradient of about 0-1 M of an elution salt, wherein the monomer is purified from the dimers or multimers or both present in the mixture, and wherein the monomer yield is greater than 90%, and    (c) recovering the monomer.    
     
     
         2 . The method of  claim 1  wherein the polypeptide is a serum albumin.  
     
     
         3 . The method of  claim 1  wherein the polypeptide is anti-IgE, anti-IgG, anti-Her-2, anti-CD11a, anti-CD18, anti-CD20, anti-VEGF, or IgE.  
     
     
         4 . The method of  claim 2  wherein the serum albumin is bovine serum albumin.  
     
     
         5 . The method of  claim 1  wherein the ion-exchange resin is a cation-exchange resin.  
     
     
         6 . The method of  claim 1  wherein the ion-exchange resin is an anion-exchange resin.  
     
     
         7 . The method of  claim 1  wherein the gradient is linear.  
     
     
         8 . The method of  claim 1  wherein the gradient is stepwise.  
     
     
         9 . The method of  claim 1  wherein the elution salt is a sodium salt.  
     
     
         10 . The method of  claim 9  wherein the elution salt is sodium chloride.  
     
     
         11 . The method of  claim 1  wherein the gradient is from 0 to 500 mM elution salt.  
     
     
         12 . The method of  claim 1  wherein the gradient is from 50 to 200 mM elution salt.  
     
     
         13 . The method of  claim 1  wherein the gradient is from 0 to 50 mM elution salt.  
     
     
         14 . The method of  claim 1  wherein the polypeptide is an antibody.  
     
     
         15 . The method of  claim 1  wherein the polypeptide is a monoclonal antibody.