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LI-COR Introduces Universal Quencher For Visible and Near-Infrared Dyes

April 3, 2008, Lincoln, NE: LI-COR Biosciences introduces the first non-fluorescent quencher that does not need to be exactly matched to the donor's fluorescence spectrum. IRDye® QC-1 can quench fluorescence from a wide range of fluorophores in a fluorescence resonance energy transfer (FRET) system by pairing it with a visible or near-infrared fluorophore within the wide wavelength range of the quencher (approximately 500 to 800 nm).

IRDye QC-1 is a water-soluble, mono-reactive NHS ester dye that simplifies the labeling and purification process by allowing it to label peptides, proteins, nucleic acids, etc. through their amine group. Protease substrates using the IRDye QC-1 do not require an organic co-solvent in assay buffer systems.

IRDye QC-1 is suitable for FRET-based applications such as protease assays and was used in the development of LI-COR's IRDye HIV-1 Protease Assay Kit and IRDye Beta-Secretase Assay Kit. Further information can be found at

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