Sepharose is a tradename for a crosslinked, beaded-form of agarose, a polysaccharide polymer material extracted from seaweed. Its brand name is a portmanteau derived from Separation-Pharmacia-Agarose. A common application for the material is in chromatographic separations of biomolecules.
What is Protein G Sepharose?
Protein G is a genetically engineered protein containing three IgG-binding regions of native Protein G. Protein G Sepharose® beads display high chemical and physical stability as well as high flow rate, hydrophilicity and high gel strength. This product can be used for IgG purification and immunoprecipitation.
What are Protein G beads?
Protein G Magnetic Beads are an affinity matrix for the small-scale isolation and purification of immunoglobulins. Specifically, the beads consist of a truncated form of recombinant Protein G that is covalently coupled to a nonporous superparamagnetic particle.
Where does Protein G bind IgG?
Fc
For both proteins, the major binding site in IgG is located in the Fc part of the antibody at the CH2–CH3 interface and overlaps with the FcRn binding site. Protein G binds all human subclasses (Kd ~2×10−10 M),104,105 whereas protein A generally only binds IgG1, IgG2, and IgG4 (Kd ~2×10−9 M), but not IgG3.
What is the difference between agarose and sepharose beads?
While agarose (sugar molecule derived from seaweeds) is a linear polymer made up of the repeating disaccharide units agarobiose, Sepharose™ refers to the registered tradename of a bead-formed, cross-linked agarose-based gel matrix.
How do you clean protein G beads?
Wash the immobilized protein A or G-bound complexes with 0.5 ml of the immunoprecipitation buffer (RIPA or PBS), followed by centrifugation for 2-3 minutes in a microcentrifuge at low speed (1,000-2,000 RPM) to preserve beads shape. Discard the supernatant. Repeat this wash procedure at least 3 times.
Should I use protein A or protein G?
Protein A and G are structurally very similar, but they have slightly different affinities for IgG subclasses across different species. These affinities overlap, but in general, protein A has greater affinity for rabbit, pig, dog, and cat IgG whereas protein G has greater affinity for mouse and human IgG.
How does protein G work?
Protein A/G binds to all subclasses of human IgG, making it useful for purifying polyclonal or monoclonal IgG antibodies whose subclasses have not been determined. In addition, it binds to IgA, IgE, IgM and (to a lesser extent) IgD.
How are pureprotein G sepharose® beads made?
Protein G Sepharose ® beads are prepared by covalently coupling recombinant Protein G to 6% cross-linked Sepharose ® beads. Protein G is a genetically engineered protein containing three IgG-binding regions of native Protein G.
What is the IgG binding capacity of protein G Sepharose ®?
The IgG binding capacity of Protein G Sepharose ® is >20 mg of human or rabbit IgG per mL of wet beads. Protein G Sepharose ® beads display high chemical and physical stability as well as high flow rate, hydrophilicity and high gel strength. This product can be used for IgG purification and immunoprecipitation. Store at +4°C.
How is Sepharose® made?
Protein A/G Sepharose ® is prepared by covalently coupling recombinant Protein A/G (contains five Ig-binding regions of protein A and three Ig-binding regions of protein G) to 6% cross-linked Sepharose ® beads. The coupling was optimized to give a high binding capacity for IgG.
What is the Fc region of IgG antibodies?
The high affinity of protein G and protein A for the Fc region of polyclonal and monoclonal IgG-type antibodies forms the basis for purification of IgG, IgG fragments containing the Fc region, and IgG subclasses. Protein G and protein A are bacterial proteins from Group G Streptococci and Staphylococcus aureus, respectively.
