Purified (unconjugated) Thermo Scientific Pierce Recombinant Protein A/G is useful as the basis for preparing various kinds of probes or affinity media for detection or purification of rabbit and human antibodies, especially IgG isotypes, in immunoassays and antibody purification protocols.
Features of Recombinant Protein A/G:
• Contains four Fc-binding domains from Protein A and two from Protein G • Provides binding for all antibody species and subclasses recognized by either Protein A or Protein G
The extended Fc-binding properties of Protein A/G make it a popular tool in the investigation and purification of immunoglobulins. Protein A/G binds to all human IgG subclasses, IgA, IgE, IgM and to a lesser extent IgD; however, it does not bind mouse IgA, IgM or murine serum albumin. Protein A/G is an excellent tool for purification and detection of mouse monclonal antibodies from IgG subclasses without interference from these other serum proteins. Individual subclasses of mouse monoclonals are most likely to have stronger affinity to this chimeric protein than to either Protein A or Protein G.
Properties of Recombinant Protein A/G: • Source: E. coli • Molecular weight: 50,460 (Apparent MW by SDS-PAGE: 40,000-45,000) • Form: salt-free powder • A280 of 0.1% solution: ~0.505 • Isoelectric point (pI): 4.65
Gene fusion of the Fc-binding domains of Protein A and Protein G has resulted in production of a structurally and functionally chimeric protein with broader binding than either Protein A or Protein G alone. During fusion, the Protein G gene sequence coding for the serum albumin-binding site is eliminated. This protein is expressed in E. coli and secreted into the surrounding medium during fermentation. The product obtained is consistent in quality and yield because the bacterial host is engineered to be deficient in major proteolytic activities. Binding is less pH-dependent than either Protein A or Protein G alone, occurring well at pH 5 to 8.