Protein A, derived from Staphylococcus aureus strain Cowan I, is widely used in biotechnology and immunology for its ability to bind immunoglobulins, particularly IgG antibodies. It is commonly employed in affinity chromatography to purify antibodies from complex mixtures, ensuring high purity and yield. This makes it invaluable in the production of therapeutic antibodies and research applications. Additionally, Protein A is utilized in immunoassays, such as ELISA, to capture antibodies, enhancing the sensitivity and specificity of diagnostic tests. It also plays a role in protein-protein interaction studies, helping researchers understand immune responses and develop targeted therapies. Its robust binding properties make it a critical tool in both academic and industrial settings.