Abstract: The present invention provides methods for purifying a polypeptide comprising a CH2/CH3 region, comprising binding the polypeptide to Protein A and eluting with a pH gradient starting at a low pH.

Abstract: The present invention provides methods for purifying a polypeptide comprising a CH2/CH3 region, comprising binding the polypeptide to Protein A and eluting with a pH gradient starting at a low pH.

Abstract: Methods for purifying a polypeptide from a composition comprising the polypeptide and at least one contaminant are described, which methods comprise the sequential steps of: (a) passing the composition through an ion exchange membrane, where the polypeptide and the membrane have opposite charge, at operating conditions comprised of a buffer having a pH sufficiently distinct from the pI of the polypeptide to enhance the charge of the polypeptide and a low ionic strength effective to prevent the shielding of charges by buffer ions, which cause the membrane to bind the polypeptide and the at least one contaminant, and (b) recovering the purified polypeptide from the effluent.

Abstract: Methods for purifying a polypeptide from a composition comprising the polypeptide and at least one contaminant are described, which methods comprise the sequential steps of: (a) passing the composition through an ion exchange membrane, where the polypeptide and the membrane have opposite charge, at operating conditions comprised of a buffer having a pH sufficiently distinct from the pI of the polypeptide to enhance the charge of the polypeptide and a low ionic strength effective to prevent the shielding of charges by buffer ions, which cause the membrane to bind the polypeptide and the at least one contaminant, and (b) recovering the purified polypeptide from the effluent.

Abstract: The invention provides methods of reducing fouling of ultrafiltration membranes in processes wherein virus particles are removed from aqueous solutions comprising virus particles and at least one protein by adding a surfactant or non-surfactant, non-ionic agent to the aqueous solution prior to filtration. The invention also provides methods to dissociate protein aggregates or to reduce the formation of protein aggregates by adding a surfactant or non-surfactant, non-ionic agent to the protein solution.

Abstract: The present invention provides methods for purifying a polypeptide comprising a CH2/CH3 region, comprising binding the polypeptide to Protein A and eluting with a pH gradient starting at a low pH.

Abstract: The invention provides methods of reducing fouling of ultrafiltration membranes in processes wherein virus particles are removed from aqueous solutions comprising virus particles and at least one protein by adding a surfactant or non-surfactant, non-ionic agent to the aqueous solution prior to filtration. The invention also provides methods to dissociate protein aggregates or to reduce the formation of protein aggregates by adding a surfactant or non-surfactant, non-ionic agent to the protein solution.

Abstract: The present invention provides methods for purifying a polypeptide comprising a CH2/CH3 region, comprising binding the polypeptide to Protein A and eluting with a pH gradient starting at a low pH.

Abstract: Methods for purifying a polypeptide from a composition comprising the polypeptide and at least one contaminant are described, which methods comprise the sequential steps of: (a) passing the composition through an ion exchange membrane, where the polypeptide and the membrane have opposite charge, at operating conditions comprised of a buffer having a pH sufficiently distinct from the pI of the polypeptide to enhance the charge of the polypeptide and a low ionic strength effective to prevent the shielding of charges by buffer ions, which cause the membrane to bind the polypeptide and the at least one contaminant, and (b) recovering the purified polypeptide from the effluent.