Dyes for Your Near-Infrared Imaging Needs
The first nonfluorescent (dark) quencher compatible with a wide range of visible and near-infrared fluorophores (~500 – 800 nm)
Used for FRET (fluorescence resonance energy transfer) applications such as protease assays
Efficient nonfluorescent quenching of near-infrared (NIR) dyes
Caspase-3 Protease Assay substrate
Widest available quenching range – no need to carefully match the donor's fluorescence spectrum with the acceptor's absorbance
Pair IRDye QC-1 with any visible or near-infrared fluorophore within its wide wavelength range
Quenches common fluorophores with >97% efficiency1
Many products from the IRDye Family of infrared dyes are being used in several assays from other life science companies:
1. Peng, X et al. A nonfluorescent, broad range quencher dye for Fõrster resonance energy transfer assays. Anal Biochem. 388(2):220-28 (2009)
IRDye QC-1 is available as a monoreactive NHS ester
Label peptides, proteins, or nucleic acids on amine groups
Water-solubility simplifies labeling and purification
|Solvent||Ext. Coef. M-1cm-1||Absorption Max nm||MW g/mole|
Caspase-3 FRET Assay: Fast, quantitative measurement
of Caspase-3 protease activity
Uncleaved Caspase-3 substrate is fluorescence-quenched by IRDye QC-1
Substrate cleavage relieves quenching and generates signal
No interference from uncleaved substrate
Advantages of IRDye FRET protease assays
Simplicity - just mix and read
Flexibility – no stop solution required; easy to monitor reactions over time
Sensitivity – near-infrared detection reduces background, scattering and interference caused by other compounds
Sub-nanomolar enzyme detection1
60-fold fluorescence intensity enhancement upon digestion
Suitable for inhibitor and drug candidate IC50 measurement, and high throughput screening of enzyme activity
Excellent water solubility
1. Analytical Biochemistry 388 (2009) 220-28.
Fluorogenic Caspase-3 substrate with DEVD consensus sequence
A) Quenched substrate. When excitation light is absorbed by IRDye 800CW, energy is transferred to IRDye QC-1. No fluorescence is emitted.
B) Cleaved substrate. Caspase-3 cleavage of peptide allows dye and quencher to move apart, and relieves quenching.
Transcreener ADP2 and GDP FI Assays from BellBrook Labs
LI-COR is working with BellBrook Labs to create competitive immunoassay kits for high-throughput screening (HTS). Building upon the success of prior incorporation of LI-COR's IRDye® QC-1 quencher conjugate into its Transcreener® ADP2 FI Assay , BellBrook Labs has chosen to use the same quencher conjugate in its Transcreener GDP FI Assay . The Transcreener GDP FI Assay is designed specifically for HTS and uses a highly specific, proprietary antibody for GDP, meaning that it can be used with any enzyme that converts GTP to GDP. The Transcreener GDP Detection Mixture is comprised of a GDP Alexa Fluor® 594 Tracer bound to the GDP Antibody conjugated to LI-COR's IRDye® QC-1 quencher conjugate. Measurement of GDP is done with red fluorescent intensity (FI) readout.