Fmoc-(R,R)-Cys(StBu)-Alkyne-OH (Fmoc-Cys(StBu)-Alkyne-OH)

Fmoc-Cys(StBu)-Alkyne-OH is an Fmoc-protected cysteine-derived amino acid building block containing a tert-butyldisulfanyl (StBu) protecting group and a terminal alkyne functional group. The molecule combines an Fmoc-protected amino group for peptide synthesis, a carboxylic acid for peptide coupling, and a terminal alkyne for click subsequent-chemistry-based functionalization and bioconjugation.

The tert-butyldisulfanyl group contains a disulfide bond that can participate in thiol–disulfide exchange under reducing conditions, making this building block useful for the development of GSH-responsive and redox-responsive peptide and conjugate systems. The disulfide functionality can be investigated for incorporation into stimulus-responsive delivery systems designed to respond to intracellular glutathione-rich environments.

The terminal alkyne provides a versatile handle for copper-catalyzed azide–alkyne cycloaddition (CuAAC) and other click-chemistry strategies, enabling conjugation with azide-functionalized molecules, peptides, polymers, fluorophores, and drug molecules.

The Fmoc protecting group is compatible with solid-phase peptide synthesis (SPPS) and can be removed under standard basic deprotection conditions. The compound is therefore a multifunctional building block for peptide synthesis, click chemistry, bioconjugation, and the design of GSH-responsive molecular and nanomedicine systems.

Product Name: Fmoc-Cys(StBu)-Alkyne-OH
Building Block Type: Fmoc-protected cysteine derivative
Responsive Group: Disulfide (S–S)
Response Type: GSH-responsive / redox-responsive
Reactive Handle: Terminal alkyne (-C≡CH)
Protecting Group: Fmoc / tert-butyldisulfanyl (StBu)
Applications: SPPS, peptide synthesis, click chemistry, CuAAC, bioconjugation, GSH-responsive drug delivery, redox-responsive conjugates, stimulus-responsive nanocarriers, and biomedical research.