Protein recovery

Abstract

The invention herein provides a method for recovering a polypeptide comprising exposing a composition comprising a polypeptide to a reagent which binds to, or modifies, the polypeptide, wherein the reagent is immobilized on a solid phase; and then passing the composition through a filter bearing a charge which is opposite to the charge of the reagent in the composition, so as to remove leached reagent from the composition.

1  A method for recovering a polypeptide comprising: 
 (a) exposing a composition comprising a polypeptide to a reagent which binds to, or modifies, the polypeptide, wherein the reagent is immobilized on a solid phase; and then  
 (b) passing the composition through a filter bearing a charge which is opposite to the charge of the reagent in the composition, so as to remove leached reagent from the composition.  
 
     
     
         2 . The method of  claim 1  wherein the charge characteristics of the polypeptide in the composition in step (b) are such that the polypeptide passes through the filter.  
     
     
         3 . The method of  claim 1  wherein the filter is positively charged.  
     
     
         4 . The method of  claim 1  wherein the filter is negatively charged.  
     
     
         5 . The method of  claim 1  wherein the filter is placed in line with the composition exposed to the reagent as in step (a).  
     
     
         6 . The method of  claim 1  wherein the immobilized reagent is a protease.  
     
     
         7 . The method of  claim 6  wherein the protease is pepsin.  
     
     
         8 . The method of  claim 6  wherein the polypeptide exposed to the protease in step (a) is a precursor polypeptide and the protease removes a precursor domain from the polypeptide.  
     
     
         9 . The method of  claim 8  wherein the precursor domain comprises a leucine zipper.  
     
     
         10 . The method of  claim 9  wherein the polypeptide is an antibody.  
     
     
         11 . The method of  claim 10  wherein the antibody is a F(ab ) 2  fragment.  
     
     
         12 . A method for recovering a polypeptide comprising removing a leached reagent from a composition comprising the polypeptide and the leached reagent by passing the composition through a filter bearing a charge opposite to that of the leached reagent, wherein the leached reagent was previously immobilized on a solid phase.  
     
     
         13 . A method for modifying a precursor antibody comprising a leucine zipper comprising exposing the precursor antibody to a protease immobilized on a solid phase such that the protease removes the leucine zipper from the precursor antibody.  
     
     
         14 . The method of  claim 13  further comprising passing the antibody from which the leucine zipper has been removed through a positively charged filter.  
     
     
         15 . The method of  claim 13  wherein the protease is pepsin.  
     
     
         16 . The method of  claim 13  wherein the solid phase comprises controlled pore glass beads.  
     
     
         17 . The method of  claim 13  wherein the antibody is a F(ab ) 2 .  
     
     
         18 . The method of  claim 13  wherein the leucine zipper is GCN4.  
     
     
         19 . The method of  claim 13  wherein the antibody binds CD18.