SPA 33.4kDa

Staphylococcal Protein-A (SPA) is a cell wall component produced by several strains of Staphylococcus aureus. It is a genetically engineered protein that holds five immunoglobulin G (IgG)-binding regions. The recombinant form of Protein-A is widely used in research and bioprocessing due to its high specificity for IgG.

The recombinant Staphylococcal Protein-A is a homodimeric, non-glycosylated polypeptide chain. It comprises five IgG-binding domains (E, D, A, B, C) aligned in series, containing 296 amino acids and having a molecular mass of 33.4 kDa . The recombinant protein is produced in Escherichia coli (E. coli) and is designed to have little or no carbohydrate content .

The recombinant SPA is produced by expressing a modified protein A gene in E. coli. The protein is then purified to ensure high specificity for IgG binding. The cell wall binding region, cell membrane binding region, and albumin binding region are removed to enhance the specificity .

Recombinant Protein-A functions similarly to native Protein-A and is perfect for the purification of polyclonal or monoclonal IgG antibodies . It is widely used in various research and bioprocessing applications, including:

• Affinity chromatography: For the purification of antibodies.
• Immunoprecipitation: To isolate specific proteins from complex mixtures.
• Diagnostic assays: As a reagent in various immunoassays.

Lyophilized recombinant SPA is stable at room temperature for up to three weeks but should be stored desiccated below -18°C for long-term storage. Upon reconstitution, it should be stored at 4°C for short-term use (2-7 days) and below -18°C for future use. It is recommended to add a carrier protein (0.1% human serum albumin or bovine serum albumin) to prevent freeze-thaw cycles .