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Dyes for Your Near-Infrared Imaging Needs
Product Ordering Information
-
IRDye QC-1 NHS Ester 0.5 mg
[Part# 929-70030] -
IRDye QC-1 NHS Ester 5.0 mg
[Part# 929-70031] -
IRDye 800CW/QC-1 CSP-3
[Part# 926-08590]
Online ordering is available to customers in the US only.
Dye Structure
IRDye® QC-1 Infrared Dye
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
[LEFT] Energy that is transferred from the donor (Dem) can be emitted at the acceptor's wavelength (Aem), quenching fluorescence.
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)
Dyes Quenched
[ABOVE]
Normalized emission spectra for several common donor fluorophores, and the absorption spectrum of IRDye QC-1.
All are quenched by IRDye QC-1 with >97% efficiency.
Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.
[ABOVE] List of fluorophores and spectrally compatible quenchers (shaded box = compatible). Nearly all of these common fluorophores are spectrally
compatible with IRDye QC-1. No other quencher spans this wide range or is compatible with wavelengths around 800 nm.
Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.
Related Products
-
IRDye QC-1 NHS Ester 0.5 mg
[Part# 929-70030] -
IRDye QC-1 NHS Ester 5.0 mg
[Part# 929-70031] -
IRDye 800CW/QC-1 CSP-3
[Part# 926-08590]
Dye Structure
IRDye® QC-1 Infrared Dye Products
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 |
|---|---|---|---|
| 1xPBS | 96,000 | 737 | 1243.7 |
| Methanol | 98,000 | 788 |
Applications
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.
| Fluorogenic Caspase-3 Peptide (GDEVDGAK) | % Quenching Efficiency |
|---|---|
| IRDye QC-1 - Fluorescein | 97.5 |
| IRDye QC-1 - Cy3 | 98.1 |
| IRDye QC-1 - Cy5 | 97.9 |
| IRDye QC-1 - IRDye 680 | 98.8 |
| IRDye QC-1 - IRDye 700DX | 98.8 |
| IRDye 800CW - IRDye QC-1 | 98.7 |
[ABOVE] Quenching efficiency of IRDye QC-1 paired with common fluorophores. Caspase-3 octapeptide substrate was used.
Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.
[LEFT]
Caspase-3 protease assay using IRDye QC-1 to quench IRDye 800CW fluorescence
Endogenous caspase-3 activity was detected in Jurkat cells (untreated, or treated with anisomycin (1 µg/ml) or camptothecin (1 µg/ml)
to induce apoptosis). Limit of detection was 1500-3000 apoptotic cells. A linear relationship between fluorescence intensity and cell number was
observed up to 100,000 cells. Error bars are ± standard deviations.
Reprinted with permission from Analytical Biochemistry 388 (2009) 220-28.
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.
