Sortase A

Sortase A (SrtA) is a bacterial-derived transpeptidase that serves as a critical enabling enzyme for antibody-drug conjugate (ADC) development, mediating transamidation reactions that support precise, site-specific covalent attachment of diverse functional moieties onto protein substrates. Its catalytic mechanism proceeds via recognition of a conserved peptide motif displayed on target proteins — most commonly the canonical LPXTG pentapeptide sequence, where X may represent any amino acid — followed by cleavage of the peptide bond between the threonine (T) and glycine (G) residues within the recognition motif.