Protein At Beads LX is a novel, alkali-tolerant protein A-derived medium for capturing monoclonal antibodies from larger volumes of feed by packed bed chromatography. Table 1 is Characteristics of Protein At Beads LX. Alkali-tolerant protein A (protein At) is obtained by gene recombination technology on the base of natural protein A. The ligand has no animal origin during purification. The ligand is specially designed to enhance its stability to alkali and protease.Protein At Beads LX has high dynamic binding capacity (DBC) after extended retention time and is specially designed for process feed from high-expression cell cultures with increased antibody titers. Ligand is directional immobilized to the agarose beads. The level of leakage of the ligand during elution is very low (less than 10ng ligand/mg antibody). The base matrix of Protein At Beads LX is 85 µm beads of highly cross-linked agarose derivative with excellent chemical and physical stabilities, making it ideal for process scale applications.