Protein A is a cell wall protein secreted by Staphylococcus aureus, also known as Staphylococcal Protein A (SPA). The native Protein A primarily consists of three functional regions: a signal peptide, five antibody-binding domains, and a cell wall peptidoglycan-binding region. The most extensively studied and applied portion is the five antibody-binding domains responsible for antibody interaction. This recombinant Protein A (with Cys) is produced by genetically engineering the expression of the antibody-binding domains (E-D-A-B-C) from the native protein, retaining its full antibody-binding capability. A cysteine residue has been added to the amino acid sequence terminus to facilitate site-directed conjugation. The thiol group in cysteine can partially form intermolecular disulfide bonds, leading to polymerization, which can enhance antibody-binding capacity.
Source: Escherichia coli
Molecular Weight: 34.3 kDa
Isoelectric Point (pI): 5.17
Purity: ≥ 95% (SDS-PAGE)
Form: Lyophilized
Solubility: Soluble in distilled water at ≥ 10 mg/mL
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