Patent ID: 8853371

Claim:
A method for producing a solution of purified unaggregated Fc peptide chains comprising the steps of: a) providing an aqueous sample comprising unaggregated Fc peptide chains and aggregated Fc peptide chains; b) contacting the sample with a population of protein A peptide chains bound to an insoluble material and capable of binding greater than 70% of the total mass of unaggregated Fc peptide chains and aggregated Fc peptide chains in the sample; c) contacting the population of protein A peptide chains with an aqueous solution having a salt concentration consisting of tris(hydroxymethyl)aminomethane acetate of 41 mM to 97 mM and a pH of 3.42 to 3.74; and d) removing the aqueous solution from contact with the population of protein A peptide chains to produce a solution of purified unaggregated Fc peptide chains comprising less then 5% aggregated Fc peptide chains; wherein the total percent yield of Fc peptide chains is greater than 70%.