Protein A is a non-glycosylated cell wall protein of Staphylococcus aureus that can bind Fc part of immunoglobulin molecule of different species with strong affinity. Protein A consists of five IgG binding domains (A, B, C, D, and E), each is approximately 60 amino acids long with no cysteines present and two Staphylococcus aureus cell membrane binding domains (X and M).
AnaSpec's recombinant Protein A consists of only IgG binding domains and was expressed in E.coli. Its apparent molecular mass is approximately 30,000 Da compared to the most reported 42,000 Da for the native Protein A that is found in Staphylococcus aureus. Biotinylated Protein A can be used for assay development, IHC, IF, immunoprecipitation assays, and for western blotting.