Rabbit IgG Beads 4FF is A protein A fusion product produced by a one-step purification prokaryotic expression system with rabbit IgG as the affinity ligand. Protein A is a cell wall protein isolated from Staphylococcus aureus, mainly binding to mammalian IgG through Fc fragments. Rabbit IgG Beads 4FF is based on a highly cross-linked 4% agarose gel and can be purified at a relatively high flow rate.