Used as a crosslinking agent in biochemistry for modifying proteins and peptides. Its primary application is in introducing thiol groups into amino groups of biomolecules, enabling site-specific conjugation or labeling. Commonly used in the preparation of thiolated antibodies, enzymes, and other proteins for immobilization on solid supports such as gold surfaces or activated resins. Also employed in the synthesis of disulfide-containing cyclic peptides and in studying protein-protein interactions. Due to its ability to react selectively with primary amines, it is valuable in creating functionalized biomolecules for diagnostic assays, biosensors, and targeted drug delivery systems.