S tag is an epitope tag composed of a 15 residue peptide, KETAAAKFERQHMDS, derived from the pancreatic ribonuclease A. This interactive complex (S‐tag/S‐protein) results in micromolar affinity – dependent upon pH, temperature, and ionic strength . The S‐tag itself enables colorimetric detection via western blot analysis or a rapidly detected assay dependent upon ribonucleolytic reconstitution and activity.
