Used as a key reagent in peptide synthesis and protein modification, particularly for introducing thiol groups in a protected form. The acetyl-protected thiol allows selective deprotection under mild conditions, enabling controlled conjugation or labeling of biomolecules. It is also employed in the preparation of thiolated polymers and hydrogels for drug delivery and tissue engineering due to its ability to form disulfide crosslinks. Its anhydride functionality reacts efficiently with amines, making it useful for bioconjugation strategies in diagnostic and therapeutic applications.