Table 1.10 Molecular Probes nonfluorescent quenchers and photosensitizers.

Dye Abs * Extinction Coefficient † Amine-Reactive Dyes ‡ Notes
Dabcyl 453 32,000 D2245 (SE)
  • Broad and intense visible-wavelength absorption
  • Efficient energy transfer acceptor from blue- and green-fluorescent dyes in FRET applications
Malachite green 628 76,000 M689 (ITC)
  • Nonfluorescent photosensitizer
QSY 7 560 90,000 Q10193 (SE)
  • Essentially nonfluorescent quencher
  • Broad visible-wavelength absorption
  • Efficient energy transfer acceptor from UV light–excited green- and orange-fluorescent dyes in FRET applications
QSY 9 562 88,000 Q20131 (SE)
  • Essentially nonfluorescent quencher
  • Spectrally similar to QSY 7, but with enhanced water solubility
  • Efficient energy transfer acceptor from UV light–excited green- and orange-fluorescent dyes in FRET applications
QSY 21 661 90,000 Q20132 (SE)
  • Essentially nonfluorescent quencher
  • Long-wavelength absorption
  • Efficient energy transfer acceptor from red- and near-infrared–fluorescent dyes in FRET applications
QSY 35 475 23,000 Q20133 (SE) §
  • Nonfluorescent quencher
  • Spectrally similar to dabcyl
  • Efficient energy transfer acceptor from blue- and green-fluorescent dyes in FRET applications
* Absorption (Abs) maxima, in nm. † Molar extinction coefficient in cm-1M-1 determined at the wavelength listed in the column headed Abs. These values may vary with the environment, particularly for the QSY 35 dye. ‡ (ITC) = Isothiocyanate. (SE) = Succinimidyl ester.
For Research Use Only. Not for use in diagnostic procedures.