Description

Protein A (Staphylococcus Aureus Strain Cowan I) is a high-affinity bacterial cell wall protein that specifically binds to the Fc region of most mammalian IgG antibodies. This unique property makes it an indispensable reagent in the purification and detection of immunoglobulins. It is a critical component for biopharmaceutical manufacturers, diagnostic kit developers, and research institutions engaged in antibody-based workflows, including affinity chromatography and immunoassays.

Application

• Affinity Chromatography Resin: Immobilized on solid supports (e.g., agarose, magnetic beads) for the high-purity capture and purification of monoclonal and polyclonal antibodies.
• Immunoprecipitation (IP) & Co-IP: Used to isolate specific antigen-antibody complexes from cell lysates or biological fluids for proteomic and interaction studies.
• Diagnostic Assays: Conjugated to enzymes, fluorophores, or other labels for use in ELISA, Western blotting, and lateral flow assays to detect antibodies or antigens.
• Cell Surface Staining (FACS): Fluorescently labeled Protein A is used in flow cytometry for detecting surface-bound antibodies on cells.
• Therapeutic Antibody Production: A key tool in downstream processing during the manufacturing of monoclonal antibody (mAb) therapeutics and biosimilars.
• Immunoaffinity Purification: For the purification of IgG subclasses from serum, ascites fluid, or cell culture supernatants in research and production settings.

Basic Information

Product Name	Protein A (Staphylococcus Aureus Strain Cowan I)
CAS No.	91932-65-9
Molecular Formula	Contact for details
Molecular Weight	~42 kDa (Single chain); varies with form
Synonyms	Staphylococcal Protein A; SpA; Protein A, S. aureus; IgG Fc-binding protein; Affinity chromatography ligand; Immunoglobulin-binding protein; Recombinant Protein A; rProtein A; Staphylococcal enterotoxin
EINECS	Contact for details

Quality Control

Our Protein A is produced and tested under stringent quality management systems. Each batch is characterized for purity, binding capacity, and biological activity to ensure consistent performance. Certificates of Analysis (COA) detailing specifications such as purity (by HPLC), endotoxin levels, and ligand leakage are provided and available upon request. Production can adhere to relevant guidelines for use in biopharmaceutical processes.

Storage

Preserve in a tightly closed container, protected from light. Store at 2-8°C. The product is hygroscopic (moisture-sensitive). For long-term storage of solutions, consider aliquoting and freezing at -20°C or below to maintain optimal activity.

Specification

Item	Specification
Appearance	White to off-white lyophilized powder
Identification (IR)	Conforms to reference standard
Purity (HPLC)	≥ 95%
Protein Content (Biuret)	≥ 90%
Binding Capacity	≥ 20 mg human IgG/ml resin (for immobilized form)
Endotoxin	< 10 EU/mg
Solubility	Soluble in water and standard buffers (e.g., PBS)
pH (1% solution)	6.0 - 7.5

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.