Fmoc-Cys(Acm)-OH is widely used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It serves as a protected cysteine derivative, where the Fmoc group protects the amino group, and the Acm (acetamidomethyl) group protects the thiol side chain of cysteine. This protection is crucial to prevent unwanted side reactions during peptide chain assembly. After the peptide synthesis is complete, the Acm group can be selectively removed under mild conditions, allowing for the formation of disulfide bonds, which are essential for the correct folding and function of many peptides and proteins. This chemical is especially valuable in the synthesis of complex peptides that require precise disulfide bond formation, such as hormones, enzymes, and therapeutic peptides. Its stability and compatibility with standard SPPS protocols make it a preferred choice in peptide chemistry.