A U.S. Patent for “Protein Purification” was awarded to Genentech on December 10th, 2019. The present invention is a method for purifying an antibody from a composition comprising the antibody and a contaminant, which method comprises the following steps performed sequentially: (a) binding the antibody to a cation exchange material with an equilibration buffer at a first conductivity, wherein the amount of antibody in the composition loaded onto the cation exchange material is from about 15 mg to about 45 mg of the antibody per ml of cation exchange material; (b) washing the cation exchange material with a wash buffer with a conductivity… Learn More