The origin of Protein A is from the bacteria Staphylococcus aureus. Protein A is capable of binding most classes and subclasses of immunoglobulins from goat, rabbit, mouse and human.
Protein A beads are produced using genetically engineered form of Protein A. Nonessential regions have been removed while leaving the immunoglobulins binding sites intact. The recombinant Protein A has been immobilized to agrose beads using TargetLock chemistry, in order to create a more stable product for the affinity purification and immunoprecipitation of various mammalian immunoglobulins.
Protein A beads are being routinely used for the isolation of IgG from several species of mammals. The binding of Protein A to IgGs vary between animal species and between IgG subclasses within the same species. Major limitation of protein A lies with the weak binding it
presents towards mouse IgG1, a common IgG subclass. Despite that, Protein A possesses useful
properties that make it a popular choice for the isolation of most types of IgGs. Protein A binds IgGs through the Fc region of the molecules leaving the Fab region available for binding the antigen. Protein A Beads are commomnly used for antibodies purification and for the isolation of immune complexes by Immunoprecipitation.
Protein A Beads Specifications:
Matrix:
Sepharose CL-4B
Coupling method: TargetLock.
Protein A Density:
2-4mg/ml of resin
Binding Capacity:
~4-8mg rabbit IgG per ml of resin
Mean bead size:
40 -165um
Bead structure:
Highly cross-linked spherical agarose, 4%
Max back pressure:
0.3 MPa, 3 bar
Max. flow rate:
4 ml/min/cm2
Recommended flow rate:
1-3 ml/min/cm2
Stability of the matrix:
pH 2-11
Storage and Stability:
May be stored at 4 degrees C. Do not freeze. Stable for at least 6 months.