Used in biochemical research as a cysteine analog to study enzyme mechanisms, particularly in thiol-dependent enzymes. Acts as a building block for peptide synthesis where a modified sulfur-containing amino acid is required. Also employed in the development of enzyme inhibitors due to its structural similarity to natural amino acids with altered reactivity. Its thioether linkage and carboxyl groups allow for metal coordination, making it useful in studies involving metalloproteins or metal-catalyzed reactions.