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FMOC-Lys(Dye)
FMOC-Lys(Dye) building blocks are essential tools for incorporating fluorescent labels and quenchers directly into peptide sequences during solid-phase peptide synthesis (SPPS). AAT Bioquest offers a comprehensive selection of FMOC-protected lysine derivatives conjugated to fluorescent dyes, dark quenchers, and biotin—enabling researchers to synthesize labeled peptides for FRET-based assays, protease substrates, and biotin-tagged peptides without post-synthesis modification steps.
Fluorescent FMOC-Lys Derivatives
Green Fluorescent Dyes
Green fluorescent FMOC-Lys building blocks incorporate FAM (carboxyfluorescein), FITC, or TF2 dyes onto the lysine side chain for in-sequence labeling. These dyes (Em = 516 ~ 525 nm) are commonly used as FRET donors paired with TAMRA, Cy3, or dark quenchers like DABCYL. FAM and FITC are among the most widely used fluorophores for peptide labeling due to their high quantum yield and compatibility with standard fluorescence detection equipment.
Key Features
- TF2 (Tide Fluor™ 2): Excellent and more affordable replacement for Alexa Fluor® 488 with comparable brightness and photostability
- 5-FAM isomer: Pure single isomer for consistent labeling and reproducible results
- 5/6-FAM mixture: Cost-effective option when isomer purity is not critical
Orange/Red Fluorescent Dyes
TAMRA, Cy3, and TF3 (Tide Fluor™ 3) building blocks provide orange/red fluorescence (Em = 569 ~ 578 nm). These dyes are versatile—they can serve as FRET acceptors when paired with green donors (FAM, FITC) or as FRET donors when paired with far-red acceptors (Cy5) or dark quenchers.
Key Features
- TF3 (Tide Fluor™ 3): Spectral properties identical to Cy3 with excellent brightness
- Cy3: Classic cyanine dye with established FRET pairs and broad instrument compatibility
- TAMRA: Industry-standard orange dye for FRET peptides and protease substrates
Far-Red Fluorescent Dyes
Cy5 is a far-red cyanine dye (Ex/Em = 651/670 nm) commonly used as a FRET acceptor in peptide-based assays. The red-shifted emission minimizes interference from autofluorescence and enables multiplexing with green and orange fluorophores.
Dark Quencher FMOC-Lys Derivatives
Dark quenchers are non-fluorescent acceptors that absorb energy from excited fluorophores without re-emitting light, providing low-background FRET detection. AAT Bioquest offers both classic quenchers (DABCYL, QSY series) and proprietary Tide Quencher™ (TQ) building blocks optimized for specific donor wavelengths.
Key Features
- Tide Quencher™ 2 (TQ2): Superior quenching efficiency for FAM/FITC donors; best-in-class performance for green fluorophore FRET pairs
- Tide Quencher™ 3 (TQ3): Optimized for TAMRA and Cy3 donors; excellent for orange/red FRET pairs
- DABCYL: Classic broad-spectrum quencher with established literature precedent
- QSY-7: Effective quencher for Cy3, Alexa Fluor® 546, and TAMRA donors
- QSY-21: Far-red quencher optimized for Cy5 and Alexa Fluor® 647 donors
Biotin FMOC-Lys Derivative
FMOC-Lys(Biotin)-OH enables direct incorporation of biotin into peptide sequences during SPPS. Biotinylated peptides can be used for affinity purification with streptavidin resins, immobilization on streptavidin-coated surfaces, or detection with streptavidin conjugates.
This document (01.0327.251203r1) was last updated on Sat Feb 28 2026. All trademarks and registered trademarks mentioned herein are the property of their respective owners.