Fmoc-L-Lys(Trt)-OH is a protected amino acid derivative of L-lysine bearing an N-(9H-fluoren-9-ylmethoxycarbonyl) (Fmoc) group on the α-amino function and a trityl (Trt) protecting group on the ε-amino side chain. The molecule contains both an α-carboxylic acid and protected amine functionalities, with the side chain providing a masked primary amine that can be deprotected for chemoselective peptide coupling while the Fmoc group supports stepwise solid-phase or solution-phase assembly. In peptide chemistry, it is used as a building block to incorporate a lysine residue with controlled reactivity, enabling preparation of protected peptide intermediates and labeled or functionalized peptide targets after orthogonal deprotection.
CAT No: CP25154
CAS No:11061-54-2
Chemical Name:N-alpha-(9-Fluorenylmethyloxycarbonyl)-N-epsilon-trityl-L-lysine
Fmoc-L-Lys(Trt)-OH is an Fmoc-protected lysine building block bearing a Trt (trityl) protected side-chain amine, corresponding to the L-stereochemistry at the α-carbon. The molecule contains an Fmoc carbamate that masks the α-amino group for controlled peptide coupling, a free carboxylic acid for C-terminal activation, and a Trt-protected ε-amine that suppresses side reactions during standard solid-phase or solution-phase assembly. The orthogonal protection pattern (Fmoc for the α-amine and Trt for the ε-amine) creates a predictable deprotection sequence, enabling selective exposure of functional groups for subsequent derivatization or peptide elaboration. The presence of a chiral center and two protected nitrogen sites makes the compound a practical intermediate for stereochemically defined peptide construction and downstream functional amino acid modification.
1. Peptide Synthesis
Fmoc-L-Lys(Trt)-OH is used in peptide synthesis as an orthogonally protected lysine residue that supports stepwise N-terminal assembly while maintaining the ε-amine in a Trt-protected state. The Fmoc group enables iterative coupling cycles by temporarily blocking the α-amino functionality, while the free α-carboxylic acid participates in amide bond formation after activation under peptide coupling conditions. The Trt protection on the side-chain amine helps prevent branching, cross-linking, or undesired side-chain coupling during lysine-rich sequences. The resulting lysine incorporation supports the preparation of peptides, peptide fragments, and protected peptide intermediates used in structure-activity relationship studies and synthetic methodology development.
2. Side-Chain Functionalization
Fmoc-L-Lys(Trt)-OH is applied to side-chain functionalization workflows where lysine ε-amine chemistry is introduced after controlled deprotection of the Trt group. The orthogonal protection scheme allows selective generation of a reactive ε-amino handle for subsequent acylation, alkylation, sulfonylation, or conjugation chemistry without disturbing the Fmoc-protected α-amino terminus during earlier synthetic steps. The ε-amine can be used to install solubilizing groups, linkers, or affinity tags that tune peptide solubility and molecular recognition. Downstream derivatization enables generation of lysine-modified peptide analogs and functionalized intermediates for biochemical research and applied molecular design.
3. Bioconjugation Chemistry
Fmoc-L-Lys(Trt)-OH is suitable for bioconjugation-oriented intermediate preparation in chemical biology and protein labeling pipelines that require defined lysine incorporation. The protected lysine side chain provides a controlled entry point to introduce conjugatable amine functionality, supporting the construction of peptide-based linkers used for attaching probes, polymers, or biomolecule-targeting motifs. The stereochemically defined L-lysine backbone and the protected nitrogen pattern help maintain structural fidelity during synthesis, enabling consistent conjugation sites in downstream biomolecule modification. Lysine-containing conjugates derived from this building block can serve as scaffolds for labeling reagents, affinity reagents, and analytical standards used to probe biomolecular interactions.
4. Protein Engineering
Fmoc-L-Lys(Trt)-OH is employed in protein engineering and peptide-to-protein design contexts where lysine residues must be introduced with controlled chemoselectivity. The α-carboxylic acid and Fmoc-protected α-amino group facilitate incorporation into longer peptide segments that can later be used as building blocks for protein fragment assembly or for generating defined peptide domains. The Trt-protected ε-amine enables selective post-assembly functionalization, supporting installation of reactive groups for cross-linking, immobilization, or interaction mapping. The resulting lysine-bearing peptide constructs support synthetic access to engineered biomolecular interfaces and can be adapted for studies of sequence-dependent structure and binding behavior.
5. Pharmaceutical Manufacturing
Fmoc-L-L-Lys(Trt)-OH is relevant to pharmaceutical manufacturing supply chains that require reproducible protected amino acid building blocks for peptide drug substance and peptide intermediate production. The Fmoc/Trt orthogonal protection strategy supports predictable protection-deprotection sequences during manufacturing-scale peptide synthesis, helping manage chemoselectivity for lysine-containing sequences. The free carboxylic acid functionality supports standardized peptide coupling operations, while the protected ε-amine reduces side reactions that can complicate purification and downstream processing. This makes the compound applicable as a controlled intermediate in fine chemical synthesis for peptide-based active ingredients, process development, and manufacturing of peptide fragments used in larger assembly steps.
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