Protein A is a cell wall protein secreted by Staphylococcus aureus, also referred to 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. Among these, the five antibody-binding domains are the most extensively studied and applied due to their antibody-binding function. Recombinant Protein A is engineered by selecting the antibody-binding domains (E-D-A-B-C) from the native Protein A for genetic recombination and expression, retaining the complete antibody-binding capability of the native protein.Molecular Weight: 40.0 kDa