Protein A Concentration: 1.0 mg/ml (by UV absorbance at 280 nm)
This product has been assayed against 1.0 ug of Human IgG in a standard capture ELISA using pNPP (p-nitrophenyl phosphate) as a substrate for 30 minutes at room temperature. A working dilution of 1:500 to 1:2,000 of the stock concentration is suggested for this product. Optimal titers for other applications should be determined by the researcher.
Protein A is a surface protein of S.aureus which binds IgG molecules by their Fc region. In serum, the bacteria will bind IgG molecules in the wrong orientation on their surface which hinders opsonization and phagocytosis. Mutants of S. aureus lacking protein A are more efficiently phagocytosed in vitro, and mutants in infection models have diminished virulence.
Due to its affinity for the Fc region of many mammalian immunoglobulins, protein A is considered a universal reagent in biochemistry and immunology.
Secreted; cell wall.
has not yet been referenced specifically in any publications.