Our dye/quencher labeling offer

We offer a full-range of dye-quencher FRET pairs and fluorogenic substrates.
The tables below list the dyes and quenchers available to label your custom peptides

FRET Pairs
Dye (donor) Quencher (acceptor) Donor Ex/Em
Mca Dnp

 325/393 nm


 335/493 nm


 492/518 nm


 494/519 nm

HiLyte™ Fluor 488 QXL®520

 502/527 nm

CyLyte Fluor 3 QXL®570

 550/564 nm

HiLyte™ Fluor 555 QXL®570

 550/566 nm


 541/568 nm

Rox QXL®610

 568/591 nm

CyLyte Fluor 5 QXL®670

 648/663 nm

HiLyte™ Fluor 647 QXL®670

 650/675 nm

CyLyte Fluor 7 IR-QXL®

 750/773 nm

QXL® and Dye pairings are available from our custom labeling services & from our catalog SensoLyte® protease activity assay kits
(ie., QXL® 520 - HiLyte™ Fluor 488, QXL® 520 - FAM)

Why use FRET?

FRETand fluorogenic substrates are more sensitive than chromogenic substrates with linear dynamic range and great reproducibility.
FRET-based peptides are used in a variety of applications, with high benefit when used as protease substrates in high-throughput inhibitor screening & drug discovery.

Customize your FRET Peptide


Using Dyes and Quenchers from AnaSpec (Eurogentec's US subsidiary) offers many advantages:

  • Unique collection of proprietary quenchers (QXL®) which tandem with the most popular dyes
  • Top quality HiLyte™ Fluor dyes
  • Access to the Cy dyes at an affordable price (CyLyte dyes which have identical structures to the trademarked Cy®)
  • Longer wavelengths for improved sensitivities
  • Easy adaptation to high throughput screening assays


  • Protease activity detection & measurement
  • Protease-based drug target screening and discovery
  • High throughput screening of protease inhibitors

Featured Citations

FRET-based trilateration of probes bound within functional ryanodine receptors.

Bengt Svensson,Tetsuro Oda, Florentin R.Nitu, Yi Yang, Iustin Cornea, Ye Chen-Izu, James D.Fessenden, Donald M.Bers, David D.Thomas, Razvan L.Cornea1

Biophysical journal. 2014 Nov 4;107(9):2037-48. https://doi.org/10.1016/j.bpj.2014.09.029

From AnaSpec (Eurogentec's US subsidiary) : DPc10 peptides either unlabeled, or labeled with HiLyte Fluor 647 (HF647)

Selective Homogeneous Assay for Circulating Endopeptidase Fibroblast Activation Protein (FAP)

Travis W. Bainbridge, Diana Ronai Dunshee, Noelyn M. Kljavin, Nicholas J. Skelton, Junichiro Sonoda and James A. Ernst

Nature Scientific Report 2017 Oct 2;7 : 12524. 10.1038/s41598-017-12900-8

From AnaSpec (Eurogentec's US subsidiary) : Fret peptides containing an amine-terminal donor (HyLite Fluor 488 or Cy5.5 for aP NIRF) and a dark quencher (QXL 520 or QSY21 for aP NIRF) conjugated to a supplementary C-terminal lysine

AMCA to TAMRA long range resonance energy transfer on a flexible peptide.

A. Synak, R.Fudala, I.Gryczynski, L.Kułak, S.Shah, I. E. Serdiuk, B. Grobelna, P.Arłukowicz, A.Kubicki, P.Bojarski

Dyes and Pigments. 2018 Nov;158:60-64

From AnaSpec (Eurogentec's US subsidiary) : Lys(AMCA)-Gly-Pro-Arg-Ser-Leu-Ser-Gly-Lys(TAMRA)-NH2 peptide